You shouldn't host parties without your roommate's permission.
Brandon's apartment roommate usually prefers a quiet environment so that he can study.
Brandon wants to have a party at his apartment.
Brandon asks his roommate if they can have a party and his roommate agrees to have one on a night they don't have to study.
Brandon throws a party at his apartment without asking his roommate first.
Brandon's roommate enjoys a break from studying and his grades don't suffer.
Brandon's roommate feels disrespected and can't study for an important test.