I'm not sure what I hate the most but...
1. When a comedic anime inevitably forces a serious situation near the end in order to form some kind of conclusion. Excel Saga comes to mind, though it was ironic fashion - there are plenty of love comedies or slice of life ones that end on this painful, bittersweet, overly sappy conclusion.
2. Using a transfer student as a means of generating conflict or pushing the plot forward. It's just so very hackney at this point, especially when there's one every other episode like with Infinite Stratos.
3. The repetition of the shonen battle-manga formula of the protagonist losing in competition to his (as it usually is a he) rival or arch nemesis, somehow surviving, dwelling on the defeat, seeking some new power which dwarfs his former capabilities, then having a rematch resulting ultimately in victory. There simply must exists a better way to do things then rehashing this over and over and over again.
4. When they force sympathy for the villain. Naruto did/does this far too much. Either the sympathy should flow naturally from the story telling, or it shouldn't happen at all.
5. With the rare exception of Baccano! and the Melancholy of Suzumiya Haruhi - I hate disjointed chronology in story telling - like when they start in the middle of story and then return to the beginning simply because they want to introduce all the characters early to draw interest.
6. Transformation sequences.
7. When they use 3-D CGI when two-dimensional animation would simply fit better. Nodame Cantabile and Gundam Seed come to mind immediately.
8. Repetition of stop-action sequences in lieu of actually spending the effort on animation.
9. When a character is supposedly killed at some point - only to be miraculously revived later.
10. When it's so close to being pornography, it's like.. why bother? You might as well just go for the real thing. Queen's Blade is hardly alone, but it stands out.