That's a great question I've never thought to ask myself. I can go weeks (months sometimes) without dealing with people. Sometimes it's unhealthy (like when it gets to be borderline agoraphobic), but at other times I just enjoy the lack of anxiety & "chill" of time alone. It's a really thin line now that I think of it. I think picking up on my feelings of depression & anxiety are a big part of it. I'm one of those people who has a problem identifying what I'm feeling - I tend to go with the flow. That's why I have a therapist...But there are times when I shut her out, too. That's a real "chicken-egg" question you've got there.