Cosby Show was legendary, until Raven entered the picture. And Fresh Prince was funny as hell, until Nick entered the picture. And The Flintstones owned your shit, until Bam Bam entered the mix. Most of these shows seem to jump the shark as soon as some new kid is introduced halfway through it's run. Oh yeah, Different World was excellent the first few years as well. I've watched all these shows recently, and they've had no problem holding up.