18. 'Ren and Stimpy'
Happy happy joy joy! It's probably the most lovingly animated show of all time, every frame bursting with in-jokes and detail, and maybe the only pre-Spongebob Squarepants cartoon that's hilarious with the sound off. Pairing a highstrung chihuahua with a dimbulb optimist cat, the self-consciously retro riff on Fifties kids' entertainment sent its animal duo down wormholes of "space madness" and, courtesy of a happy helmet, into conniption fits of bliss. The fact that John Kricfalusi's insane attention to the art of cartooning was used for hairballs, boogers and Cronenberg-ian body horror (at least before he was fired by Nickelodeon after the first two seasons) is all the better.—CHRISTOPHER R. WEINGARTEN