Biff gropes and is going to rape Lorraine (this is in the supposed comedy btw) and is then knocked out by George

Retarded RLM audience
>Hahaha dat was so funny da way the big bully was knocked out by skinny dork guy LOL

Non-retarded general audience
>Moment of triumph and catharsis that George not only stood up for himself, but inadvertently saved his son Marty, leaving folks watching uplifted