Qualities of a good/bad college roommate?

Heading back to the dorms soon, and I want to be a good roommate! I’ll probably be moving in before my suitemates get in and I’m thinking I’ll bake some cookies for when they arrive. What general qualities, in your opinion, make a good or bad roommate?

Answers that avoid hyperbole would be most helpful; I already know that good roommates don’t pee on each others’ beds.