worst ending ever

Which anime do you think has the worst ending ever?

Out of all the shows I've seen, I'd have to say Bobobo has the worst ending. After wasting 70 episodes to build up the plot, they end the show right at a cliff hanger. It felt like a big slap to the face.

The first Negima Anime.

"Oh, we don't have enough episodes left to start the next story arc, so let's kill the female main character, then make up some tragic backstory explaining why she died and revive her an episode later with the power of love, friendship and time travel!"

I still don't know what they smoked to make this seem like a good ending, but i sure want some of that...