I watched four episodes of Princess Tutu today, because I am too lazy to study. I love mahou shoujo (magical girl- a show that focuses on a young girl given a magical ability and her coming of age) shows that have just a bit of darkness to them. I think it is because for a fairy tale like story like many of these shows have- Tutu is full of old stories given a new twist, Fancy Lala seems like a Cinderella tale, and even Sailor Moon is taking off of the Snow Queen in the Nehelenia arc(the first 6 episodes of Sailor Stars, the 5th series of Sailor Moon), there needs a real villain for the story to have resonance.
Anime has more freedom than American cartoons, so I really don't get the fans who love Disneyfied anime with things being cheery and happy all the time. Give me drama, give me laughter and tears. I want something I can feel, not just something pleasant.