Interacting with people can sometimes be exhausting. Trying to be polite, think of things to say, read how the other person is feeling/what they’re thinking, etc. can be very tiring. Sometimes it’s just easier to be alone with your own thoughts and not have to worry about conversation with others. I think this is due to the introvert in me, but I don’t think it is necessarily a bad thing. There is a lot to be said for dedicating time to one’s thoughts because ultimately I think it leads to a better understanding of oneself and, in turn, of the world around us.