Dogs simply do not have the capacity for abstract thought in the way that humans do, so you'll never figure out why your dog is behaving in a certain way if you're trying to interpret it in human terms.
If you're having trouble with a certain activity or command, try taking away the treats for a week or so to see if he'll improve without them.
Even if you have a dog with an excellent temperament and he comes from a long line of champions, he's still going to have his moments of confusion and stubbornness.