I hate it when people say that they drink and that's fine but smoking is bad for you. Uhm, I don't know if this is news to you guys- they can both cause damage. (I admit that smoking is worse, I'm just saying) Especially if you develop an addiction. I guess smokers tend to be more "addicted" than drinkers but whatever..
I also think that people smoke for basically the same reasons they drink. To reduce stress, or just chill with friends.
One more thing, I think that as we get older we drink more. Like, just from personal experience, I didn't know many people who drank freshman year. But since then, pretty much everyone has started or at least tried at some point. So in Aubrey's post, I think the fact that you are all seniors makes it more likely that more people are drinking.