It's not okay to take out your emotions on pets.
Wilbur is feeling upset and frustrated because his dad has punished him for a minor reason.
Wilbur wants to relieve his tension.
Wilbur takes the dog out for a long walk, so he can clear his head.
Wilbur disciplines the dog even though it has done nothing wrong, so he can feel like he still has some power.
Wilbur's dog is happy to spend time outside with someone it loves.
Wilbur's dog is confused and starts to become afraid of Wilbur.