Biff Tannen was a truly awful dude and it's very weird that the first film's "happy ending" involves him dedicated to a life of servitude to the family of the woman he attempted to rape. But sometimes, especially when you're dealing with the '80s, you have to just let go, let god, and let movies be movies. Because, at the very least, there's all the manure.
In all three films, Biff Tannen/Buford "Mad Dog" Tannen, finds himself buzzcut-deep in manure thanks to our scrappy hero, Marty McFly.
Initially, Biff doesn't care for manure.
Then his feelings escalate.
Then his feelings escalate so hard as to reverberate through time.
But the lost victim in all this is D. Jones Manure Hauling, formerly the business of A. Jones back in the 1800s. Thanks to Biff's reckless driving (in fairness, as a result of a small teen boy on a proto-skateboard or dangling through the air on a string) they lost loads of sh*t on this human load of sh*t. I hope they have insurance.