Ideally college should teach you how to learn, to set a foundation for the rest of your life. At least in the U.S. though, inadequate high schools and overpopulated junior-level classes mean that you spend the first 2-3 years of college being pumped through a mind-numbingly mechanical process. If you're lucky in your fourth year you'll start to really be challenged to think for yourself.

The kind of teaching you really want to encounter in college requires close, direct interaction with a mentor. In practice you don't actually get that much of this.