For me, it was Mirai Nikki.
[spoiler]I swear, 10,000 years later and Yukiteru is still moping like a bitch? I would have thought that he would have eventually gotten over Yuno. Seriously, I mean, yeah he fell in love with her, but moping 10,000 years for a bitch that made you kill your friends and then try to kill you is really stupid.[/spoiler]
Post yours, my floody buddies.
-
Sword Art Online. In fact every episode past the first few. I've never seen an anime that showed so much promise go downhill so fast.