Oh, there have been plenty - usually I just think "I don't really want to see more of this" and it sort of falls lower in my priority list of things to see, until if falls right off without me making the decision consciously.
Last ones I remember specifically were Beelzebub, Sword Art Online, and Muv-Luv Alternative: Total Eclipse.
Beelzebub failed to make me laugh once, and I'm not that hard of an audience really. It was like watching a watered down version of Cromartie High mixed with the early episodes of Kateikyoushi Hitman Reborn. I wasn't particularly impressed with its action, art style, plots, or characters either really.
Sword Art Online just floundered around, it went from being surprising and dramatic with interesting protagonists to fairly predictable with highly conventional protagonists. This could be me, I wanted this series to go a certain way and saw things in it that weren't really there, but I choose to blame it.
Muv-Luv Alternative: Total Eclipse, on the other hand, I just couldn't forgive. The writing was so stupid, the characters boring and obvious, and it was just so infuriating because the opening episodes were so dark and teased you with the prospect of a cheesy sort of Lovecraftian horror mixed with a cheesy sort of mecha - two things which are of interest to me and were handled well enough for those episodes. Then time skip forward and I get whiny crap with characters I hate working towards some annoying harem romance/comedy and... just... awful.