A few come to mind.
In Fullmetal Alchemist and Trigun, I really hated the formulaic episode structure. Ed/Vash roll into town, identify a problem, fix it, leave. Over and over again.
Neon Genesis Evangelion had no lovable (or even hate-able) characters, so I didn't give a damn what happened to any of them, thus was bored.
Black Butler, while not as formulaic, had the same problem with lack of progress as Fullmetal and Trigun did.
Flipping through channels, I stumbled across Naruto and Bleach a few times. While I don't know a thing about them, they looked awful. The voice actors in Naruto sounded like constantly yelling, chain-smoking ten year olds, and Bleach seemed extremely emo. But again, I've seen roughly 10 minutes of each.