Many people expect from me for a strong justification when I announce I don't drink. They come up with all sorts of theories: maybe religion issues, maybe my drunk parents would beat me up in childhood or, my personal favourite, I'm an AA and erasing my heavy drinker past is part of my therapy. They usually get very disappointed when I can't come up with a really good story.
There isn't a good story behind my choice. I grew up getting used to the fact that drinking is a part of your path into social coolness, boosting your peer-success and filling up the book of memories with alcohol related episodes - most of them, decadent, humiliating and, to my eyes, deeply sad. Sometimes, to add some drama, I say I promised to my late grandmother, in her death bed, that I would never drink. They fall for it and I always get that tender-eyed-sided-head puppy-lover "ooohhhhh" reply. *Sigh*