After the first week of classes, among all the greetings and nervous first conversations with your classmates, you might find that the most interesting people you met were your professors.

We think they’re interesting too, and a lot of them remind us of other professors we’ve had during our time in college. So we put together a list of the most memorable types of professors that you might encounter in the classroom.

Your Cool Professor

One of your favorite professors will probably be the one who treats you the most like an adult. She is also the one who runs her class more like an optional club meeting than a college course. “Call me [insert first name]!” she will insist the first day of class. It seems a little inappropriate, so you don’t really take to the habit.

It’s easy to become friends with this professor. You respect her a lot since she tends to joke openly and candidly with you. She makes you want to impress her, which is good — that’s how your “cool” professor gets you to do your best in her class.

Your Activist Professor

Another common type of professor, a personal favorite, is the in-your-face, ideological kind. As your teacher, this professor believes it’s her job to give you the selling points of her school of thought. She might advocate feminism, liberalism, conservatism, nihilism (but hopefully not) or anything else you can think of. But whatever it is, she wants you to believe in it, too.

This professor is a tough grader, but it’s only because she wants you to use the same deep thinking that led to her passion. You find that you can use this difficulty to really grow and learn a thing or two in this professor’s class. What makes this professor especially valuable is that she believes in her students as much as her radical ideas.

Your Toughest Professor

Of course, things can’t always be hunky-dory in the classroom. You will inevitably have a real stickler for a professor at some point in your college career. This type-A (as in “automatic failure”) professor is hard to please. He skates all over your paper with his red pen and has a lot of “NO EXCEPTIONS” written into his syllabus, too.

Professors like this can be stifling. If nothing else, learn how to crank out an “A” with the little wiggle room that you have.

Your Obnoxious Professor

We all have bad habits, and professors are not immune. You might find that your professor says “uhh…” way too often when he speaks. Sometimes, he has even worse habits, like blowing his nose in the middle of class, or developing blossoms of sweat stains in all his clothes (we know, it’s hard to think about). Or maybe he’s just bad with technology — that can be pretty annoying, right?

It’s important not to judge, though. Surely the person sitting next to you gets annoyed when you click your pen or tap your feet. Heck, even the professor with the bad habits probably can’t stand that.

Your Eccentric Professor

And some professors aren’t immune to bouts of insanity. You remember your high school art teacher who threw a pencil across the room at a sleeping student? Yeah, we have that teacher here, too. She also openly curses in class and gives scatterbrained lectures that recall your art teacher’s most infamous tirades.

We don’t have many tips for surviving a class with this professor. It’s going to be a truly unpredictable semester. Keep your ears open, though. We hear that some of her philosophies can be surprisingly insightful.

All jokes aside, these comical stereotypes should never define a professor for you. It can be easy to pigeonhole someone, but professors are as diverse as students, and that makes them fascinating. Make an effort to get to know your professor while you’re in class with them. Who knows what you’ll learn.