Alcyhol is the by far the most used and easily available. If you switched it with pot, it would be a mellow party. If you switched in X, DJ Dan would be a lot richer. If you switched in cocaine, well, I would be more concerned. PCP, same way. Heroine, everyone would be laid out, but none of them would be at college in the first place.
For some reason, beer just fits perfectly.
It's just head-shakingly depressing to think about how vilified alcohol WOULD BE if it were a newly discovered drug. If we were a nation of potheads, and beer were suddenly invented, we'd outlaw that sucker in a minute. But since it's 'socially acceptable', WOD-lovers rationalize all manner of chaos that it creates.