Never mind the nasty habit of throwing garbage out of car windows — Brazilians are tidy people, who sometimes shower twice a day. Everyone is expected to change clothes daily, wash hands when coming in from the streets, and brush teeth after every meal (have you noticed Brazilian teeth?).
So if you’re staying at a Brazilian guesthouse or hostel, keep it clean, take out the trash, make your bed, use deodorant. And always take a shower before going to bed. Always.