Why would anyone ever want to stop drinking?
I can think of a few reasons.
What if you were getting hammered 4 or 5 nights a week in college. That's cool. It's just a college phase, even if your GPA is a 2.7. What if you woke up after blackouts next to girls whose name you didn't even know? What if you got drunk and hooked up with a random the night before the LSAT (and have a below average test day --167). What if you might've knocked up some hippie a month later, only you won't know if the kid is yours until it's born in august --days before law school orientation. And then what if you got blackout drunk about a dozen more times after that. Then one morning you wake up naked and confused (you always wake up this way after a blackout, although you don't think you've ever woke up in urine before) having been banned from your favorite bar. You have no idea what you did, but it must have been horrible because you're a very regular customer and an excellent tipper.
Then you get to thinking... the banstick from your favorite bar is an all-time low. Waking up in your own fluids and impregnating some dumb girl didn't stop you, but banned from your bar... Then you get to thinking that you should've drown in your own vomit a long time ago... and if you don't shape up quick you'll fu(k up law school.
...that'd probably make you wanna stop.