Naruto. I mostly watched the first series & very little on Shippuden. Why did I stop watching? Mostly because I came to question why the hell I ever got into the series? Granted I read the manga first then watched the anime version, but at some point I wondered what the hell makes it so special. I stopped giving a damn series after, in the manga, Obito was revealed to be Tobi (big shocker) & how he & Madara were kept alive all this time. Also, it's partly cuz of the fandom I now more or less hate Naruto. I wish for it to end soon, and/or the series & some of its characters to just die, period.