Happiness is being alone every now and then, and happiness is coming home again.
Even *I* like to be alone every now and then. Don't think you're special just because you find time alone restful, or productive, or whatever; thus, preferable to a less solitary activity. I believe that independent self-study is a very necessary component in the mastery of any skill, and it is through mastery of skills that we develop confidence in our ability to deal with life's challenges.
Basically being good at stuff makes us feel good about ourselves.
That being said, the premise of development of personality Is that somehow, somewhere, conscious, unconscious, whatever mix you desire, our brains made a ruling on what works best for us. Naturally, you're going to prefer those things.
Going back to solitude. To Illustrate, I have a neurological disorder that makes it difficult for me to ignore external stimuli which has an effect on my ability to focus.
In other words I rolled low constitution Why does this matter? It makes me particularly sensitive to distractions. Most people do not appreciate having their thoughts disrupted.
The best way to prevent your thoughts from being disrupted is to remove distractions.
This doesn't mean I hate people, I just would prefer a quiet environment when I'm trying to concentrate. Likewise... say you prefer an activity like introverted thinking that does not require external stimulus... you're going to prefer an environment conducive to the completion of such processes. Namely one that does not bombard you with unnecessary input that you need to sort through in order to maintain focus.
If you like to be alone, it doesn't mean you hate people. It just means your find your thoughts interesting and deserve attention and focus. And they probably are.
Now... if you think people are boring, you're obviously not doing it right.
You can't know people are boring unless you know people.
If you think that your thoughts are way more important/interesting than the thoughts of others, you either:
A) Are a Narcissist
B) Don't know people
C) Think you know people, but really don't.
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Conclusion: While being an INFJ may not specifically indicate a preference for being alone, I would not be surprised if samples showed high incidence of such a behavior. I don't think a sample of people who self identify as introverts is enough evidence prove the anything more than coincidence and would be highly skeptical of any claims that state any definite causal correlation based solely off a bunch of people on the internet saying it is so. While such may be a very good indicator and provide a number of possible plausible explanations, further investigation would be necessary in order to examine the verity of any such claims.
I guess what i'm trying to say is. Correlation does not imply causation.