Epigraphs are like little appetizers to the great entrée of a story. They illuminate important aspects of the story, and they get us headed in the right direction.
When his life was ruined, his family killed, his farm destroyed, Job knelt down on the ground and yelled up to the heavens, 'Why God? Why me?' and the thundering voice of God answered, 'There's just something about you that pisses me off.' –Stephen King
Wow, God. Totally not cool. Not cool at all.
This quote from Stephen King's Storm of the Century references the Book of Job in the Old Testament of the Bible. You can probably guess what it's about from the quote, but we'll sum it up for you anyway:
Job was a fine upstanding man, who never did bad stuff, got along with everyone, and loved God. The Devil told God that Job only like God because things were going so well, and God was like, "Oh yeah? Go ahead and destroy his life, and let's see what happens." So the devil killed Job's family, destroyed his home and his farm, took away his money, and gave him several horrible and disfiguring diseases. Job kept on praising God, and finally asked at the end why he had to suffer so much. God's answer is basically, "Because I felt like it."
The thing that's interesting about Stephen King's version is that he takes the Devil out of the equation and implies that God just likes seeing Job suffering. In other words, Job is being tortured by a jerk.
And, that's basically your plot of There Is No Dog. Bob doles out suffering and happiness randomly, whether or not the people are good or pious or whatever. In other words, we can can totally see him saying that to Job. In fact, he probably did.