During Latin last semester, I spent 90% of class time trying to figure out why I inexplicably hated certain people. After careful analyzation, I was able to establish 10 types of people that irritate me by existing. They are present in every classroom, and spotting them has become one of my favorite ways to pass class time. That, and drawing pictures of them being defenestrated. It's like voodoo but with sharpies.

1. The dumb bitch.

She doesn't understand how passing around the attendance sheet works and will manage to skip an entire row through sheer stupidity. She's probably taking notes in neon pink, and interrupts to ask for spelling clarifications every 30 seconds. If asked to read out loud, she will stumble over all words longer than two syllables. If corrected, screeches, “Yeah, that's what I said!”

2. The old guy with the rolling backpack.

Because clearly 67 is a great age to start a new career. He's too weak to lift said backpack up the stairs, resulting in a lot more noise and the occasional split backpack, which is hilarious to watch but painful to be behind. Makes the younger professors incredibly uncomfortable every time they have to correct him. His vision isn't what it used to be, so he's in for a surprise when he finally gets that long-haired “girl” he's been hitting on all semester to go home with him.

3. The kid who only showed up to sign in.

Will fall asleep within 10 minutes and get skipped for the attendance sheet because his sleep-flailing annoys everyone around him. Halfway through class he'll wake up with a startled snort, see he missed sign in, and leave noisily to see if any of the couches in the union are available to continue his nap on without the annoying drone of the professor's voice in the background.

4. The gym rat.

Recognizable by the fact that he's holding a Gold's Gym protein shake (because the newly redesigned, state-of-the-art campus gym just won't do, and he wants to make sure we all know it) and flexing instead of taking notes. This kind of guy likes to strut in late so everyone can see that he was too busy pumping iron (while admiring his own reflection) to get to class on time. Wears a sleeveless shirt in the middle of winter because he's under the impression that his biceps won't fit in sleeves. They will.

5. The hungover girls.

Will wobble to their seats in last night's clothes and spend the entire class discussing their plans for the night and complaining about how loudly the professor is talking. This only happens Tuesdays and Wednesdays because the rest of the week they're still too trashed from the night before to show up.

6. The 40 or so people that only show up on test days.

While usually the room is just over half full, on test days these people magically appear and fill the room, leaving the regulars to wonder who they are and where they've been all semester. Even the professors look disconcerted when they walk in and realize that actually half the class did not drop out, and they're going to have to send the grad student to make more photocopies of the test.

7. The guy who won't stop humming.

Usually has poor social skills and tends to be wearing a World of Warcraft shirt. Shuts up halfway through class because the dragon he's drawing instead of taking notes distracts him. To his credit, the dragon is probably pretty lifelike. Is a junior but still extremely proud of his high school chess club accomplishments. Ladies, he's single.

8. The girl with all the causes.

Her backpack and clothes are covered in “save the insert-name-of-cute-fuzzy-creature-here!” pins, she passes out flyers for some eco event at the start of every class, and she'll lecture you about tree murder if you use a new sheet of paper rather than writing on the back of the previous one. Don't point out that her flyers are also tree murder, she'll pin a button to your skin and then claim it's okay to hurt you because you're not an endangered species.

9. The phone addict.

Usually sits in the back corner of the lecture hall so she doesn't get asked to leave. If in a classroom, sits near the door so she can go in and out easily as her phone rings. Halfway through class, the professor will lock her out, separating her from her phone's charger. Will perform Oscar-worthy hallway theatrics upon discovering this.

10. The bored grad student TA.

Sole responsibility: clicking the “next” arrow on the projector remote to get to the next slide. Somehow 4 years of college and some grad school weren't enough to prepare her for this challenging role. She could not have the correct slide up if her life depended on it. Every time she switches to a new incorrect slide, the people bothering to take notes collectively sigh.