Lately, my DS4 has begun to constantly challenge the things we tell him and automatically resist doing the things we ask him to do. He disagrees just for the sake of disagreeing, even if he knows what he's saying isn't true. For example, if I say "You can't have oatmeal for breakfast because we don't have any." His response is "Yes, we do." If I say something is pink, he'll pounce and insist it's fuschia. If I say his hands are dirty, he'll insist they're clean. It's become a major battle to get him to eat anything ("I don't like the part of the pancake that's cooked"), brush his teeth, get dressed, or take a bath. He just wants his way with everything.

Has anyone dealt with this type of behavior with any success?