There was a time when I drank, but the first time I blacked out in a bar and lost my memories of most that night I stopped getting drunk. If I'm out with friends, I may have a few drinks early on. Once I hit a buzz though, I'm done for the night.
The main reason I almost stopped drinking entirely is because my father, while I was growing up, was an irresponsible drunk. I can't forget the times that he had to drive me back from a sporting event, concert, or company parties after drinking the entire time. Staring out the window and watching him swerve around the lanes, and then I'd try to fall asleep so that I wouldn't have to see an accident happen. He would do the same thing when driving me to my mom's after the weekend's I'd spend with him. Hell, when my parents were together, and I was younger, my mom had to wake me up in the middle of the night to go with her to pick him up from the drunk tank. I saw myself going down this road, including driving drunk, and I stopped. If I ever have kids, I don't want them to see what I had to see.
If you don't want to drink, don't. Peer pressure is stupid, and not worth giving into. If you are going to drink, please do it responsibly and get a DD/call a cab if you're too drunk to drive home.