Ever tried to find a good roommate who you didn’t already know? At first it seems kind of fun, like auditioning people who want to be your friend. Then someone signs a roommate lease (for a full year!) and moves in, and you realize they’re actually not nearly as cool as you thought.

Nightmare Roommate 1: Dirty Harry

Harry is probably a nice guy: funny, laid back, relaxed, and pleasant to be around. Unfortunately, he’s a filthy disgrace to the very concept of civilization, and leaves half-eaten pizzas lying around his room for three weeks on end (occasionally taking a bite or two). That science fair project-looking thing in the fridge that you can no longer recognize? That was Harry’s hamburger helper from June. If you took a black light into his room, you’re likely to lose your lunch on the spot. And then there’s the bathroom – the carpet of hair alone is enough to choke a donkey.

Slumlord Advice: Find an excuse to drop by their current home before signing that roommate lease with them, maybe to drop off their rental application. Ask to use the bathroom, and scope the place out. If it’s a biohazard zone, you know the roommate search will have to continue.

Nightmare Roommate 2: Loosey Lucy

Lucy was a cute little 24-year old, who laughed at all your terrible Confucius Say jokes, wears low-cut tank tops, and works out in her sports bra. But if Lucy’s chirping, annoying friends aren’t all over at your house chugging Smirnoff Ices and cranking Miley Cyrus, then Lucy’s bedroom antics with Eduardo, Billy Joe, Tyrone and Guido (at least you can tell them apart) are keeping you awake at 1:30 AM when you have an 8 AM conference call the next day. It’s just not cool.

Slumlord Advice: Don’t sign a roommate lease with her. The best case scenario is you mix business with pleasure, which is still a bad idea, and the worst case scenario is your marriage and career dissolve “overnight.”

Nightmare Roommate 3: “I’ll Get You Back Next Week” Homer the Hobo

They won’t get you back. If they do, they’ll be short, and it’ll be even later than they said they’d pay you. Now you have to evict the person who sleeps 20 feet away from you, who eats the same food you do, and who shares a bathroom with you, who is in a position to sabotage any of those activities.

Slumlord Advice: Run a tenant background check, and call their boss to make sure they actually make money.

The best decision you can make is to sign a roommate lease with a big nerd, who just sits in their room and plays World of Warcraft all day. No slobs, no hotties, no bums… for that matter, no one you actually know.