Thankfully, there may be something -- or several things -- you can do about it.
A study published in the journal Nature on July 11 found that when people were given the option of spending money on themselves or another person, those who spent it on someone else had more activity in a brain area linked to the subjective feeling of happiness.
Scroll down to learn why, and to discover 24 other ways to feel happier.
Focus on others instead of yourself.
We've all been there. It's been a bad day and you feel the urge to buy your favorite comfort food or snag a new pair of shoes. However, studies suggest you'll feel happier if you spend that money on someone else.
The new study in Nature suggests that people feel happier after doing something generous because activity in the brain regions involved in helping others seems to override the activity in the regions linked with personal reward.
A 2008 experiment supports these findings -- for that study, volunteers were split into two groups and either splurged on themselves or another person. Those who got something for others were shown to be happier than those who bought something for themselves.
Donating your time can have the same effect. In a recent review of 40 studies done over the last 20 years, researchers found that volunteering was one of the most successful ways to boost psychological health. Volunteering was found to be linked with a reduced risk of depression, a higher amount of overall satisfaction, and even a reduced risk of death from of a physical illness as a consequence of mental distress.
Write down how you're feeling and what you're grateful for.
Keeping tabs on the things you feel lucky to have in your life is a great way to boost your mood.
In a recent study from psychologists at UC Davis, researchers had 3 groups of volunteers keep weekly journals focused on a single topic. One group wrote about events that happened that week, the second group wrote about hassles they experienced, and the last group wrote about things they were grateful for.
Ten weeks later, those in the gratitude-journal group reported feeling more optimistic and more satisfied with their lives than those in the other groups. They also reported fewer physical symptoms of discomfort, from runny noses to headaches.
Even just recording your feelings is a great way to clarify your thoughts, solve problems more efficiently, relieve stress, and more.
A team of psychologists recently studied brain scans of volunteers who wrote about an emotional experience for 20 minutes a day for four sessions. They compared the scans to those of volunteers who wrote down a neutral experience for the same amount of time. The brain scans of the first group showed neural activity in a part of the brain responsible for dampening strong emotional feelings, suggesting that the act of recording their experience calmed them. This same activity was absent in the volunteers who recorded a neutral experience.
Go on a hike or gaze at the stars.
Awe is a powerful (even awesome, you might say) human emotion. A handful of recent studies have found a link between experiencing a sense of awe -- like the feeling you get when looking at a starry sky or across a wide open valley -- with decreased stressedand higher levels of satisfaction.
Drink coffee (not too much, though).
Several studies have even found a connectionbetween caffeine consumption and reduced risk of depression, as well as an even a lower risk of suicide. However, at least one of these studies found this connection with caffeinated coffee but not tea, though others found the same effect for tea as well.
You don't have to be Don Draper to reap the benefits of some peace and quiet.
Multiple studies suggest that meditating -- focusing intently and quietly on the present for set periods of time -- can help lessen feelings of depression and anxiety. Research in long term meditators (Buddhist monks, for example) shows that these peoples' brains are well developed in areas that could be linked to heightened awareness and emotional control.
While it's possible that people with such brains might be more likely to meditate in the first place, other studies show that people who complete a meditation program tend to show brain changes linked with self-awareness, perspective, and memory.
Read an adventure story.
You may be able to get some of the benefits of an awe-inspiring experience just by reading about someone else's. A small 2012 study found that people who read about someone else's adventure were more satisfied, less stressed, and more willing to volunteer to help others than people who were simply shown something that made them feel happy.
Stressed out? Head for a forest. One study found that a group of students sent into the trees for two nights had lower levels of cortisol -- a hormone often used as a marker for stress -- than those who spent the same two nights in a city.
In another study, researchers found a decrease in both heart rate and cortisol levels in people in the forest compared to those in urban areas. "Stressful states can be relieved by forest therapy," the researchers wrote in their paper.
A 2015 study also suggested that a brief walk in nature could chase away negative thoughts.
In the study, a group of 38 Northern Californians were split up into two groups -- one that took a 90-minute walk in nature and another that did the same walk in the city. The nature walkers reported having fewer negative thoughts about themselves after the walk, while the urban walkers reported no change.
What's more, fMRI brain scans of the participants who took nature walks revealed less activity in the subgenual prefrontal cortex (sgPFC), a brain region that may play a key role in some mood disorders and has been linked with patterns of negative thought. Those who went on the urban walk did not show any of these benefits, according to the study.
Work it out.
Exercise is proven to increase feel-good chemicals in the brain, reduce stress hormones, and relieve depression and anxiety according to Happify, a website and app that offers psychology-based games to increase your happiness.
You can achieve these positive changes in just a few minutes -- researchers at the University of Vermont found that just 20 minutes of exercise can give you mood-boosting benefits for up to 12 hours. Moreover, people who are active are happier and more satisfied with their lives.
The duration and location of your workout also affects how happy you feel afterward. Check out Happify for a guide to achieving your maximum happiness sweet spot.
Do things you usually enjoy -- even if you're not feeling happy.
"Positive emotions may aid those feeling trapped or helpless in the midst of negative moods, thoughts, or behaviors ... spurring them to take positive action," a team of UC Riverside psychologists wrote in a recent paper summarizing these findings.
Participate in cultural activities.
Visiting a museum or seeing a concert is yet another way to boost your mood. A studythat examined 50,000 adults' levels of life satisfaction in Norway found that people who participated in more cultural activities reported lower levels of anxiety and depression. They also had a higher satisfaction with their overall quality of life. So go see a play or join a club!
Listen to sad songs.
Happiness is entirely subjective -- something that makes one person happy might affect someone else differently. However, listening to sad music seems to be linked with increased happiness around the globe.
In a study that looked at 772 people in the eastern and western hemispheres, researchers found that listening to sad music generated "beneficial emotional effects such as regulating negative emotion and mood as well as consolation."
Move to Norway.
Ok, moving to Norway might not make you happy, but people who live there are some of the happiest in the world, according to the World Happiness Report, a ranking compiled by an international team of economists, neuroscientists, and statisticians to measure global well-being.
According to the ranking, people in the happiest countries trust their governments and businesses, see themselves as free to make life decisions, and say they have good social support.
Set realistic goals.
If you like to make to-do lists, listen closely: When setting your goals, it's better to be specific and set goals you know you can achieve. For example, instead of setting a goal like "save the environment," try to recycle more.
That example was tested on a group of 127 volunteers in a 2014 study. The first group was provided a series of specific goals like "increase recycling," while the second group had broader goals like "save the environment." Even though the second group completed the same tasks as the first group, the people in the second group reported feeling less satisfied with themselves than the first group. The people in the second group also reported a lower overall sense of personal happiness from completing their goal, the scientists reported.
Make time for friends.
Spending time with friends may promote greater happiness than spending time with family, at least according to a recent study.
For the study, researchers used an app called the Mappiness app to determine how much happier people were when they were with their friends, parents, and children.
The app sent alerts asking people how happy they felt -- on an 11-point scale from "not at all" to "extremely" -- throughout the day. By analyzing over 3 million submissions from more than 50,000 volunteers, the researchers discovered that on average, people experienced an 8% increase in happiness when they were with friends, compared to a 1.4% increase with parents, and just a 0.7% increase when they were with their children.
The study examined a group of city bus drivers over a period of two weeks. They found that employees who put on a fake smile for the job were in a worse mood by the end of the day. But drivers who genuinely smiled as a result of positive thoughts actually reported being in a better mood by the end of the day. So when you smile, make sure to mean it!
It's one thing to get upset over an injustice you suffered, but it's another thing to hold on to that emotion long-term. That's called a grudge, and it can easily consume you.
The reason grudges are bad for your happiness is that the negative emotions associated with those feelings eventually give way to resentment and thoughts of revenge. This leaves little room in your emotional repertoire for anything else, like happiness, according to the Mayo Clinic. What's more, decades of research have linked the simple act of forgiveness to better overall heart health, less psychological stress, improved physical ability, and longer life.
That's why it's always better to forgive and move on than hold a grudge.
A 2004 study suggested that increasing the amount of intercourse you have from once a month to once a week gives the same amount of happiness as receiving an extra $50,000!
But beware: more sex doesn't necessarily mean more happiness, according to a report published in 2015. The researchers of the latest study found that couples who were asked to have more sex for the study reported that the sex was not enjoyable and did not make them happier.
The researchers therefore concluded that sex will only lead to happiness when a couple is having it for a meaningful reason. The frequency is less important than the purpose behind the act.
Be a realistic optimist.
People who have the positive attitude of optimists paired with the rational outlook of realists tend to be more successful and happy, according to psychologist Sophia Chou.
That's because so-called "realistic optimists" have the perfect blend of personality types to succeed. Unlike idealists, they are willing to face challenging situations with a clear view of reality, but will use creativity and a positive outlook to try to solve the problem.
Get your hands dirty.
Breathing in the smell of dirt may lift your spirits, according to a study that found that a bacteria commonly found in soil produces effects similar to antidepressant drugs.
The harmless bacteria, Mycobacterium vaccae, stimulated the release of serotonin in the brain after it was injected into mice. Low levels of serotonin is what causes depression in people.
In a human test, cancer patients reported increases in their quality of life when they were treated with the bacteria.
The findings "leave us wondering if we shouldn't all be spending more time playing in the dirt," lead author Chris Lowry of the University of Bristol said in a statement.
Avoid eating lunch at your desk.
Sad desk lunch can be a real downer. Scientists from the University of Sussex measured the happiness of employees after they ate lunch in different locations, and found that people were happiest about their work when they ate lunch on the beach. They were least happy about work when they ate at their desk.
Getting outside in the sun was key to staving off misery -- people who ate in parks had a more positive attitude about their jobs than those who chowed down at a restaurant or at home.
Hone your favorite skill.
Working hard to improve a skill or ability, such as learning to drive or solving a math problem, may increase stress in the short-term, but it makes people feel more content in the long run, a 2009 study reported.
"People often give up their goals because they are stressful, but we found that there is benefit at the end of the day from learning to do something well. And what's striking is that you don't have to reach your goal to see the benefits to your happiness and well-being," co-author Ryan Howell said in a statement.
Be patient -- happiness tends to increase with age.
When it comes to happiness, older people seem to know something that the rest of us don't. A number of studies have found that older people tend to be some of the happiest around.
The reason why, however, is still a mystery to scientists. Chances are, it's a combination of factors: One study in 2013 suggested that because older people are more experienced, they're therefore better at dealing with negative emotions like anger and anxiety. Another more recent study suggested the cause could be that older people are more trusting, which comes with a number of healthy psychological benefits that lead to happiness.
Whatever the reason, if you're not happy right now, you can rest assured that your chances of happiness in the future are good.
This post originally appeared on Business Insider.