Haven't had a drink in over 20 years.
I drank a lot of beer in college, never developed a taste for wine or the hard stuff. After college, I was a social beer-only drinker who made the decision to quit after a near-miss DWI incident in my late 20's. I realized it might become a real career problem for me- I was traveling a lot, interacting with customers (especially Asia- now those folks like to drink...) and the easiest way for me to control it was just to stop altogether. It was the right decision at the time, and I am sure it kept me from making some bad choices on the road.
I don't begrudge anyone who drinks responsibly.