Why's that?

ROOMMATE FROM HELL

you could have done something about that long ago and you know it

like what? Commit murder?

Don't encourage me, Brian

There's also things like run them out of the room, move out, get someone who knows neither you or the roommate to commit the murder...

"Accidently" light their bed on fire...

Conveniently be moving large heavy objects while they're sitting by the open window.

all those are great ideas!