You should have respect for other people's possessions.
Garrett's car battery is dead.
Garrett wants to drive to the store.
Garrett borrow's his roommate's car, and makes sure to fill up the tank to show his appreciation.
Garrett borrow's his roommate's car without permission, and leaves the gas tank almost empty.
Garrett's roommate is grateful and happy he can save money on gas.
Garrett's roommate is angry and has to pay the refill the tank.