Nadia -- Originally planned for 27, but high ratings extended it to 39, with disastrous results--12 episodes of bad animation, reckless handling of the story and characters, and bizarre Looney Tunes-ish gags that are nowhere to be found in eps. 1-22 or 35-39. Only parts of 30 and 31 had any real value to the plot. I don't remeraber being this badly disappointed with filler episodes other than these.
Slayers TRY -- As much as I like Slayers, I felt that the series was becoming somewhat stale with this third season. In particular, I felt that the writers were running out of ideas for entertaining filler episodes. The Lina in Wonderland episode, the Justice Warriors episode... those were all dull and forgettable. (I hope Revolution's filler episodes aren't similarly lame, but who knows.)
Fullmetal Alchemist -- I love this show, but I am very weary about having another season. I felt that they closed things off appropriately in the final episode and the movie (to a lesser extent). I only hope it won't at least be poorly animated, boring, or messy.