The tumblr Pete Campbell's Bitchface ensures you'll never have to wait for the next episode of Mad Men to see the delightful expressions "everyone's favorite little shit" makes while blackmailing Don, refusing to discuss adoption, and offering sexist fashion advice.
I love Pete. He's whiny, he's petulant, he's entitled, he's immature. He's basically the only one acting like a kid when everybody else his age is acting like my grandpa.
I think he's presaging the youth revolution and the onset of extended adolescence. He's the only character who acts like somebody his (ok, my) age would act today and I find him fascinating to watch for that reason.
Neither I nor anybody I know has the serene competence of Joan or the forward-thinking ambition of Peggy, but everybody I know has fake called in sick to work to eat Cheerios in their PJs and watch cartoons.
Also, I think Vincent Kartheiser is hot, so there's that.