Plenty of studies show that people who socialize more tend to be happier. At face value that makes sense: relationships, friendships, spending time with people we enjoy... all of that makes us happier.
But that's not true if you're highly intelligent. If that's the case, socializing with friends will not increase your level of satisfaction with your life.
Let's take a step back. Researchers followed people between 18 and 28 years old. They found the more most of the people socialized, the happier they were -- but not the subset of people studied who were highly intelligent.
The more they socialized, the less happy they were.
The researchers offered several explanations. One was evolutionary in nature: Greater intelligence lets smart people more easily adapt to a modern world where close contact with a social group -- for food, shelter, protection, etc -- is no longer as necessary.
Another theory is aspirational in nature: The smarter you are, the more focused you will be on longer-term goals, and spending time with friends is distracting rather than helpful.
In short, if you're hanging out with me... you aren't getting stuff done.
Of course, this is just one study and may be only directionally accurate -- after all, I like time alone but I'm not particularly bright.
But in your case, if you like to spend time alone working on a project, learning something new, writing that business plan, or grinding away at all the steps you need to take to reach your goals, don't feel like you're a loner.
You may just be smarter than the rest of us.