I like any show that have realistic (and/or) reasonable story in any genres.
I like normal/realistic romances with normal main caracters (for ex. "lovely complex" and "toradora" are unrealistic in my opinion)
And i only like supernatural shows that has reasonable story and ending. (Because sometimes when an anime is supernatural, the creators think that they can use any supernatural events that doesn't mentioned before or doesn't fit with plot to complete it when they runs out of story!)
Also i don't like horror, tragedy, sad endings and harsh life shows.
+ Note that anything may have an exception!
The plot, character development, last episodes (how anime ends) are the most important parts for me.
Animation really doesn't factor much for me, except when it seriously degrades through the show.
however if it drawn with details, can improve my score :)
Note that if i learn something from an anime, this certainly improves its score.
Sometimes i rate an anime low but it is good, that is because of a reason. (for ex. Akame ga kil was very good but i hate its ending) :|