What makes people drunk when drinking beer?

Personally I don't like to get drunk - it's a very expensive way to embarrass yourself.

However, several of my friends would and did get drunk on a regular basis. For them, it was a social identity (being a party-person), a way to meet people (at the bar or club), a way to relax and reduce inhibitions, and a way to forget for a little while any problems they were having.