I live with a 260 pound English mastiff. She's very sweet, but I usually have a bruise somewhere at the end of the day because she was a little insistent with a pat "request," or happened to walk on my foot.
I don't have a particular favorite, but we used to have several very smart mice in our cellar (which got there by themselves). My mom set out a live trap, but the mouse would always take the bait without springing the trap. Needless to say the longer this went, the more I secretly cheered on the mice.