While there are really shitty places like this, it's almost getting to trope levels on the Internet.

The wait staff/bartenders I knew/know all do it because it was by far the highest paying job you could get. Especially with part time hours. There isn't much else you can do as a college student that will pay any better. And if you are very good, attractive, and get a bit lucky on where you work you are talking white collar pay levels per hour.