I had recently used Dominate Person on a giant and he failed his ST. Due to our horses (but not our cart) getting caught in an explosion, I decided that I would just get our giant to pull the thing. As soon as I did, our GM said that the giant gets a new ST with the +2 bonus because he "doesn't want to pull the cart". By that logic, we could go on to say that no creature wants to be under the effects of Dominate Person and as a result, would get an ST every round, even out of combat. My question is; What would ultimately be considered against someone's nature?