Crayon Shin-chan - I don't get how people can watch poorly drawn crap and enjoy it.
Iron Man - This disappointed me beyond all reasoning.
Naruto - After Sauske vs Naruto 4 episodes in I knew where it was headed and I was right. Just a ton of fillers.
Naruto Shippuden - I didn't learn from the previous Naruto.
Tantei Opera Milky Holmes - One episode and I dropped it knowing very well where it was headed. People said there was no fan service or ecchi stuff in it so what's the point of watching something that you already know the ending of?