I was just discussing this with a friend at work today. My circle of friends is now very small (not that I complain, I like how close we are); but a few years ago I'd have a huge contact list on my mobile. I also find I don't even enjoy going out clubbing as much, when before, I'd be down at different clubs every single weekend.
I guess I wore it all out very soon. Too much partying, drinking, meaningless conversations and "friendships". Not to mention dangerous situations and drama.
I like who I am NOW much better. I still have fun and go out and get some drinks, only not as often and with company that's worth it. And yeah, I really have to be in the mood to socialise in order to. Sometimes I just want to be home alone reading or watching a movie. Two of my fave hobbies!