When I was eleven, one rainy evening during Thanksgiving weekend, my mother put my brother and I through a terrifying twenty-minute ride (on the wrong side of the road, sometimes) before running a red light, crashing into another car, then spinning around and hitting a stoplight so hard it fell over. I had known, when we got into the car, that she was too drunk to drive, and I felt awful knowing that I had almost asked my dad not to let her drive us but didn't have the balls to follow through.
Thankfully, no one got seriously injured, and spending a couple of hours in jail and losing her license actually allowed my mom to realize that she'd been an alcoholic for seven or eight years and needed to stop drinking, but at that point, I promised myself that I'd never drink. At about the same time, because my parents both smoke pot, I vowed never to smoke. It's hard to rebel against a couple of hippies, really.
I've managed to politely decline the now-almost-weekly invitations that I get to smoke pot with my increasingly drug-minded friends (one close friend and one acquaintance have started dealing in the past year), and I've kept my drinking so far to very occasional, very light social drinking. Will I continue to be such a prude? I don't know. But for now, that's how I'm different from my parents.