When a TV show survives beyond a couple of seasons, it will often deviate from the arc laid out in the pilot. It's only natural: child actors grow up, audiences fall in love with unexpected characters, Roseanne Barr gets bored and wants to piss the world off. Good shows learn to adapt.
Ultimately, it's hard to keep the attention of the television-consuming public for 30 minutes, let alone a decade. This list is a celebration of how drastically some of your favorite shows changed from pilot to finale: