It's rude to deposit snow onto a roommate's car.
Emily is getting ready to leave the house and head to school.
Emily wants to get to her destination quickly.
Emily digs the snow out from her own car and piles it in the yard where it is not in anyone's way.
Emily digs snow from around her car and dumps it on her roommate's car to save time.
Emily gets her car out quickly and leaves no mess behind.
Emily's roommate is angry at Emily because she has to take extra time to dig her car out.