What do you do during your leisure time and do you find it enjoyable?

Why do some people prefer to be alone most of the time?
I prefer to be alone. I typically don’t connect with people, and I don’t want to. I don’t dislike people, or feel like they are not good enough to be my friend, nor am I concerned that I am not good enough to be theirs. I just really enjoy being alone.
When I was in college. I had people with whom I used talk to, but I find that after several minutes of conversation, I have “had my fill” socially, and excuse myself. I never feel isolated or lonely, but after a brief conversation, I feel content and want to go elsewhere and be by myself. I spend time with some extremely close personal friends. Aside from them, I feel no desire for companionship.
I have always been like this. I am not unhappy, I do not feel excluded, lonesome, or depressed about it. On the contrary, when people push me for social interaction, I feel aggravated, uncomfortable, and pining for my solitude. When I go out with other people, I feel bored and sluggish, counting the minutes, and waiting for an opportunity to leave. I am not particularly shy, nor am I viewed as strange, or antisocial. I am normal and nice, but I just want to be left alone.
I hate being called, I hate getting text messages, and I hate the pressure to respond. Whenever I get a text or call from someone I don’t want to talk to, my heart races. Maybe it’s some kind of social anxiety but I don’t feel “anxious” in social situations. But I hate being asked to go out somewhere, and texting or talking on the phone feels tedious and forced. I like people, I just feel like my desire to interact with them is very, VERY limited.