The transition from high school to college is typically one of the biggest transitions you'll make in your entire life. But not on TV. On TV, it's just high school without your mom and dad.
There are so many High School tropes that if a work relies on them, it's got real trouble once its characters graduate. To prevent them from graduating out of the story, the story follows them to college, but they still want to use the same tropes, hence why college seems to be exactly like high school. You've still got a stuck-up principal, only this time he's called the "dean" (and he might have fancier glasses). You've still got characters seeking a Wild Teen Party, only now they're part of Wacky Fratboy Hijinx. The students are still the same types of characters; you've still got Jerk Jocks, Valley Girls, and nerds, and you've still got youth-induced relationship drama. You've still got lockers into which to stuff the nerds, and you've still got bells and hall monitors to tell you when class is supposed to start.
As with many tropes, this one runs a spectrum. In some cases, it's just a way of showing that people don't grow up that much the minute they turn into independent adults, or even explicitly describes college antics as something these guys had wanted to do all through high school but couldn't because of high school's authority figures. This is particularly common in "frat comedies" like Animal House or in fictional sororities, where the women will usually be tyrannical and unpleasant. But on the other end of the spectrum, the authority figures are just as active in college as they are in high school, leading to such insanity as professors putting college students in detention for texting in class.
The reality, as always, is not as it is on TV, but the extent to which it differs depends on the institution. Most universities will acknowledge that their students are adults and treat them accordingly, so they won't micromanage them — i.e. they don't particularly care if you don't show up to class, because it's your life and your education, and if you want to waste it, go right aheadnote . But some professors might dock your grade for things like not showing up on time or using your phone in class. And while the teachers and administrators aren't usually going to get on your case for misbehavior, there usually is a separate campus police who'll do it. There's also, obviously, a big cultural divide between certain institutions; a college in the American South will worship its football players much like an equivalent high school might, but you won't see that happening at Oxbridge.
Perhaps the biggest mistake of this trope is mistaking the level of intimacy in a university. Most universities are bigger than your average high school, meaning it's nearly impossible for everyone to know everyone else, and furthermore it's much easier to just avoid dealing with drama. The local Jerk Jocks aren't going to be stuffing the nerds into lockers (not that colleges have lockers outside maybe the gym, and only athletes are going to see the inside of a locker room) without someone totally unrelated to either of them stepping in, but that's the kind of thing you might see with this trope.
A Sub-Trope of Artistic License – Education. See also California University, for the phenomenon of a cast of high schoolers all going to the same college after graduating.
