Answer:He simply just snapped. He definitely looked angry before Joey even started talking to him, and said how he hated being there...and he already had an axe in his hands...he just lost it, and took out his anger and frustration on Joey.
Answer:My theory is Vic was a diabetic and was acting in self-defense, since Joey just tried to kill him with a candy bar.
Answer: He simply just snapped. He definitely looked angry before Joey even started talking to him, and said how he hated being there...and he already had an axe in his hands...he just lost it, and took out his anger and frustration on Joey.