In the movie, after Grace leaves Bruce, when Bruce is trying to teach the dog how to go to the bathroom outside, he says something along the lines of "I hate to admit it but they're laughing at you. OK get it straight, house bathroom, bathroom house." As he says this, he points to each one, and on the second one he points to the house and says "bathroom" and then he points to the pole where he wants the dog to go to the bathroom and says "house." It is a really trivial mistake, but definitely a mistake. Oops!