gratuitous violence
Gratuitous violence is violence for the sake of being violent. Usually assocciated with low budget movies and cult videogames. Given without need, often unrealistic.
Grand Theft Auto had a Gratuitous violence bonus.
gratuitous violence
Fighting over how much to tip the waiter/waitress. Also fighting between servers over the tip itself.
"Lunch went well, except for the decision on how much to tip, which erupted into gratuitous violence."