I teach college at a non-elite large public university.
Worst part - seeing how bad the U.S. education system is. I'd say 40% of the students we get aren't prepared at all for college and (quite honestly) don't belong in college. I'd say they'd be better off not going to college, but that's not entirely true, because non-college grads are discriminated against in the workforce when they shouldn't be.
And to rub salt in the wound, we get pressured to pass people even if they're clearly not qualified. (The pressure is not explicit, but it's through the incentives built into the system.) That waters down the meaning of a college degree, and in some ways I'm ashamed to say that some of these peoples have degrees from our institution.
Best part - the students who are actually good and want to learn, you can really make an impact on their lives. The other good part is how flexible the hours are and how secure the job is.