I'll just say it now - I hate alcohol.  Hate, hate, hate it.  It smells disgusting, and it makes people act incredibly stupid, forgetful, and regretful.  

My friends and I are not old enough to be legally drinking, which is a separate issue. What concerns me more is that multiple friends of mine have gotten into drinking - and getting wildly drunk - just for the fun of it.

I don't know what to do in this kind of situation.  I have no respect for people who get wasted for fun, but these people are my friends.  I don't want to lose them just because they're into something I'm not - but I can't pretend to be okay with what they do.  Some of them have had drinks around me without telling me, and since I have trouble telling when people are drunk, I usually have to find out later - at which point, I've even been lied to about it.  I end up feeling betrayed, and I hate hearing stories about them getting drunk and doing stupid things, even when it didn't happen around me.  It makes me disgusted with them, and I worry that I'll lose my friends because I can't handle their habits.

What would you do in this type of situation? How do you handle friends whose habits you can't support?