There are many things I would not do by myself. These I do now because they encourage social activity. I think its a pretty long list. Some things I would probably not do by myself are:
1) Drink chai so regularly - I would not even make myself a morning cup, I'd drink water
2) Eat so much, and so unhealthy - I eat little when alone, stuff myself in company
3) Take useless pictures - I would click rarely, observe more
4) Watch movies - I'd prefer looking at a lake, trees,
5) Read bad books - I'd be outside watching the sky
6) Have pointless conversations - Obviously cannot, saves loads of time, energy
7) Drink - Don't think I'd ever be able to drink alone
8) Get into unnecessary dramas - Communication is the mother, so I'd avoid dramas
9) Crack jokes, laugh - I'd be smiling at best
10) Spend, save - But why?
11) Bother about the kind of clothes to wear - How does it matter?
12) Browse tv, internet endlessly - Saves loads of time that I normally 'kill'
13) Second guess myself about everything - No one to impress so I'd just go with the flow
14) Stick to 'established timings' - Sleep, work, eat, wake etc when you want
15) Feel sad - I'd probably appreciate life a lot more than to feel sad
I guess I need to make a 'Things I would do by myself' list too - to get things in perspective.