Most anime that I don't like I end up forgetting. I don't think about them again unless someone brings them up. Everyone has different tastes right? But sometimes an anime drifts into my "unpleasant feeling" category. That's bad.
I think an anime deserves bigger negative points if it's the type of anime you would think you would normally like, but you don't. It's a lot easier to dislike and complain about an anime because it's not the TYPE of anime you normally like.
Anime where my main reason for dislike is because of the female lead:
Akage no Anne
Brigadoon
Rizelmine
Tenshi ni Narumon
Comedies that were wacky in a way that got on my nerves. They don't have my kind of humor at all:
Amaenai de yo
Final Approach
Hanaukyo Maid
Katekyo Hitman REBORN!
Kidou Shinsengumi Moeyo Ken
Koi Koi Seven
Lime-iru Ryuukitan X - One of the most disliked shows of all-time by the people who have seen it.
Mamotte Shugogetten
MAR
Miami Guns
Okusama wa Joshi Kousei - I think she is the only Ayako Kawasumi voiced character that I've ever disliked. I guess the idea of having a romantic comedy about holding in your feelings is annoying to me.
Okusama wa Mahou Shoujo - I should never again watch an anime with "Okusama" in the title.
Shijou Saikyou no Denshi Kenichi
Tokimeki Memorial TV series
Tsuyokiss - Why did they hire a director who didn't like the game's characters, personalities and character designs and so he changed them?
UFO Princess Valkyrie
Disliked adult anime:
Kiss Yori (Heat For All Seasons) - Why is he getting mad at his girlfriend being unfaithful when he's doing the same thing? I can't take either side. They're both acting like idiots.
Pendant - What horrible CG artwork. The characters frequently look like their noses are cut off.

I didn't think the story was very good either. Something really went wrong with the production I think.
Anime I don't like mainly because of the artwork:
Air Master
Alexander -
Three more that don't fit a category:
Macross 7
Master of Epic
Texhnolyze