Before I start, I want you to know that I don't like ALL anime, as my friends think I do. There are some anime that I really don't like, for example, Boku no Pico, Pokemon, and School Days.

Now starting with this list.

10. Stupid characters made only for fanservice. I could go on and on about this one, but I simply cannot stand male characters thrown in your face for fanservice. They are useless.
9. Kagome.
8. It's overrated. They tried so hard to combine romance with shonen and a little bit of fanservice.
7. Way too many episodes.
6. The fandom is just...
5. Wayyyyyyyyyyyy too many episodes. Hundreds of episodes, somewhere around 40-something volumes, a lot of OVAs.