Theme/message of the movie
It's a simple theme/message in my opinion: crime doesn't pay
Vincent: Hitman who ends up shot dead in a bathtub
Jules: Finds religion but presumably gets killed when he tries to leave the business
Butch: Cons Marcellus, ends up in a car crash, taken hostage and almost raped
Marcellus: Widely known and feared as a mob boss, hit by Butch with the car, taken hostage in the pawn shop and raped
Maynard: Rapist/enabler, killed with Samurai sword
Zed: Rapist, shot in the genitals by Marcellus, presumably castrated for his actions
Mia: Cokehead, nearly ODs by snorting heroin
Brett and his friends: Get involved with a mob boss, end up shot dead in their apartment.
Realistically, Butch has the only relatively happy ending in the movie.