Naruto would be so much better if there wasn't so much filler and flash-backs every two seconds. Even so, Shippuden still my 4th favoriete anime haha but I can see how it could be considered overrated.
Black Butler is overrated to me. It took me a while to actually finish this anime (I dropped it 2 different times, once on the 3rd episode and then I tried again and dropped it around the 5th episode). But once I actually stuck to it, it got better but really the only thing the toon had going for me was Sebastian. I also couldn't stand Grell but after fully watching the anime he became one of my favorieten in the anime. But overall, I still didn't really care for the story line and most of the characters get on my nerves. I just don't see what all the hype and fandom is about. Just wasn't for me... I tried though.
For me it would definitely have to be Shingeki no Kyoujin. It seemed that the opening was much meer exciting than any of the actual episodes, until the opening song started to annoy me too...I just don't get excited over a plot that revolves around killing things and the deaths of characters I couldn't bring myself to care about. It might have been different if the characters weren't so annoying and trying to be blatantly "philosophical" about their nihilism. One can only hear "It's a cruel world" so many times.