I admit it. I have several. I think I am almost influenced by mood, but for me it also depends on the genre. When dealing with my romances (I do so love them), I am all about the monsters being monsters. For some reason redemption stories rub me the wrong way. If I have an alien, let the alien be true to their nature and culture.
I can totally get behind the huge sweetheart @Sunny, especially if it's like the RAWR MONSTER, but I luffs you bats eyes and swoons. Haha.
I also admit to being a bit like @Occi when it comes to certain types of relationships. There seems to be an almost trope within certain romance genres that make me cry, and one of them is the whole constant miscommunication. I can get behind a couple instances, but if every 2 chapters the characters are not talking, or having issues that could have been resolved by talking, I get annoyed. It's okay the first few times, especially if they come from different species, or cultures, etc, but after a while, it gets grating.
One of the things I absolutely love is having a character that is underestimated. So, if I work with vampires, or things that live long, I love the idea of a character that looks young, but could probably out think, out fight, and out maneuver.
Another huge stereotype I love to create is one that is the complete antithesis of me. It's fun to take a character and go "If I were in this situation I would do this." and my character is all "Hah, no. We do the absolute opposite." And I watch what happens. Exploration in a safe way!