Each of us, on average, has around 27,000 days to live. Subtract a third or so of that for sleeping and another chunk for those early years you don't remember and can't control, and you're left with a pretty terrifyingly low number.

I'm not saying that to depress you. I mention it because, as great philosophers have reminded us, remembering the shortness of life is what spurs us all to live authentically. When you're cognizant of the fact that time is short, you value it appropriately.

And when you value time appropriately, you don't want to waste it. If you have any sense at all of how precious your life is, you already try to avoid obvious ways to fritter away your hours and years, like too many TV binges or sticking with a job you know in your heart you're not suited for. But there are many ways to let life pass you by that are less easy to spot and therefore more dangerous. I've rounded up a few here.

1. Surrounding yourself with the wrong people

At this point, it's probably a cliché to say that "you are the average of the five people you spend the most time with," but even if this particular formulation is a little overused, the reason is almost certainly because it's true. Which makes whom you choose to spend your time with one of the most important productivity, happiness, and simply life decisions you make every day.

There are several obvious ways people can go wrong (such as spending energy dealing with manipulators and narcissists), but one of the most disastrous is also the easiest to fall into because it's based on kindness and optimism--sticking with a relationship of any sort because you think the other party will change.

That's a sure recipe for tons of wasted time, according to a host of commentators. "Relationships require maintenance, but there's a difference between maintaining a good relationship and trying to force a bad one that doesn't make much sense to begin with," points out Lifehacker's Kristin Wong. When you're fundamentally incompatible with someone (in business or in romance), cut your losses or risk wasting too much of your limited time.

2. Complaining

Spending time complaining about your problems might seem like an innocent enough way to blow off steam and bond, but according to science the effects of dwelling in that sort of head space are potentially huge. Complaining rewires your brain to more quickly and easily see negativity. Pessimism, in other words, get easier with practice. (The opposite is also true.)

So all that moaning and complaining isn't just eating into your time; it's also making it harder for you to be productive and happy. And what better way to waste your time than to miss out on opportunities--and joy--because you were too busy complaining?

3. Not asking for help

This is another huge time suck Wong warns against. Sure, asking for help can make you feel dumb, she points out, but as a brutally honest colleague once told her, "You look dumber when you don't get it because you failed to ask."

You can waste an incredible amount of life fretting about whether to ask for assistance. "Here's another way to look at it: If you're not asking for help, you're probably not challenging yourself enough," Wong writes. "There are a handful of reasons we don't ask for help, but it's usually because we're too proud or scared, and that's a huge waste of time, because it keeps you from moving forward."

4. Letting other people tell you how to live

According to Bronnie Ware, a hospice nurse who's listened to thousands of patients reckon with the inevitable end of life, there's one regret that comes up more than any other. It's not something dramatic like lost loved or missed career opportunities. Instead, it's a struggle most of us face every day--living your life according to others' expectations rather than your own true desires.

"This was the most common regret of all," she says. "When people realize that their life is almost over and look back clearly on it, it is easy to see how many dreams have gone unfulfilled."

Similarly, writer Ivan Chan warns on Self Stairway that letting others tell you how to live is a definite warning sign you're wasting your life. "Plenty of people will enter your life--well-intentioned or not--who will try to tell you how to live your life. Will you listen?" he asks. "It's your life and you get only one chance to live, so don't waste it by living dependently on the commands of others."

5. Chasing momentary happiness rather than meaning

According to science, there are actually two kinds of happiness, my Inc.com colleague Abigail Tracy has explained. "The first type, known as eudaimonic well-being, is happiness associated with a sense of purpose or a meaning in life," she notes. The second is hedonic well-being, which is just that nice glow you get when you satisfy a desire (by, for instance, scarfing a chocolate bar or buying a new TV).

Snacks and consumerism feel instantly good, while pursuing a deeper purpose by, say, starting a business or training for a triathlon, definitely isn't all smiles. But if you're always chasing hedonic happiness and not thinking about eudaimonic well-being as well, then chances are good that you're wasting your full potential. (Studies also suggest you'll probably just make yourself anxious rather than happy.) In the end, true satisfaction and joy come from meaning, not empty pleasures.

And you don't have to take my word for it. There's a ton of science digging into these two flavors of happiness and how pursuing each affects our mood and overall assessment of our lives. You can take a deep (and fascinating) dive into the research with this Science of Us post if you're interested.

6. Walling yourself off from your feelings

If all these hard-to-spot ways to waste your life share one common feature it's that we pursue them with good intentions. We complain to vent. We let other people tell us what to do out of respect and concern (and fear). We stick with a bad relationship out of love and optimism about the other person's ability to change.

Similarly, this sixth way can sound like a smart strategy: Life is a roller coaster, so walling yourself off from your emotions might seem like a sensible way to modulate the potential pain. But it's also a tremendously good way to waste your time on earth.

"You ruin your life by desensitizing yourself," cautions Bianca Sparacino on Thought Catalog. "We are all afraid to say too much, to feel too deeply, to let people know what they mean to us. Caring is not synonymous with crazy."

The impulse to protect yourself by muting your feelings is understandable, but the alternative is so much richer. "There is something breathtakingly beautiful in the moments of smaller magic that occur when you strip down and are honest with those who are important to you. Let that girl know that she inspires you. Tell your mother you love her in front of your friends ... Open yourself up, do not harden yourself to the world," instructs Sparacino.

Are there any other ways you see people wasting their lives without even realizing it?