I don't mind being alone, and often enjoy it. I also like to share time with people, but mostly with people I have chosen to spend time with. That is, I don't much like having to hang out (or work) with people who rub me the wrong way.
I have a mild, or "sub-clinical," social anxiety problem which comes and goes as it gradually falls away. The symptoms typically appear when I'm with new people, face-to-face. It almost went away altogether recently, but certain recent events have triggered the underlying causal issues, which, not surprizingly, relates to self-esteem and confidence.