Bars vary pretty widely. In college, there are the hookup type bars, generally and widely known as, well, we call them "meat markets". Those are probably the type you want to avoid, as frat boys, jocks and all sorts of people trying to get casual sex and or drunk hang around there. (There are dry meat markets as well, for example, the on campus rec pool, ARC and gyms and so on)

However at other bars (sometimes at different times), bars are considered to be far less awful. People that are regulars and other people just coming in for a drink, to watch the television and whatever, somewhat like more of a cafe environment, except with alcohol. Some bars on cater to certain groups, and so on. (Gay bars, for example, from what I've heard from girls, great places to get a drink and dance if you don't want to be bothered every five seconds by a horny guy)