8. Biff Accidentally Gave George The "Dutch Courage" To Hit Him - Back To The Future
Robert Zemeckis' legendary time travel classic, revolving around teenager Marty McFly (Michael J. Fox), who inadvertantly travels back in time to 1955, where he must play matchmaker to his future parents (Crispin Glover and Lea Thompson) to ensure his own existence.
Back to the Future is just a perfect storm of first-rate writing, direction, acting and special effects colliding together, allowing it to effortlessly endure over almost 35 years.
The Twist You Didn't Notice
Pretty much every time travel movie in existence boasts a plot twist or two, but the first two Back to the Future movies feature one hilariously ironic reverse-setup-and-payoff pertaining to George McFly (Glover) eventually knocking douchebag bully Biff Tannen (Thomas F. Wilson) out.
In isolation, the first film suggests that George simply mustered up the courage to take on Biff the old fashioned way, but Back to the Future II quite blatantly implies that he had a little liquid encouragement.
You see, the sequel shows Biff spiking the punch at the high school dance, and the first film showed George drinking said punch before he, uh, landed his punch. There's no fudging needed here - the cause-and-effect is pretty much iron-clad.
After all, what's more beautifully ironic than Biff himself literally giving George the necessary "courage" to beat him up?
Granted, series co-writer Bob Gale denied that he ever intentionally wrote George being drunk into the original script, but we're gonna invoke a little Death of the Author here and say that the logic is tight enough to win out.