Everyone has stress to deal with. When your roommate is moody, irritable, or unreasonable try not to take it personal. This should be obvious but the lack of consideration is a frequent complaint. If your roommate is asleep keep the music down or if he is studying for a test it may not be the best time for a party. Yes, your roommate may be different from you but that does not make him a weirdo.
All people are fundamentally the same.
Everyone has hopes and dreams. He may not like the same music as you do or he may have a foreign or southern accent but such differences can enrich your relationship. Nobody wants a nosey roommate. Do be respectful of another's property. Don't set a cold drink on your roommates speakers or borrow items without permission.