Probably just the ability to hang out and feel "normal" with a group of buddies. I can still hang out with friends but when they decide to just kick back and have few/six beers, I can't do that with them. My good friends know that I don't drink anymore and no one tries to push it on me or treats me any differently. Still when there's 3-4 guys kickin' back with some beers I still get that feeling that there's something wrong with me where I can't just be a normal guy and have a few with them and talk guy stuff.
Steve