Bob represents our experiences, as well as the experiences of others, namely experiences that don't align with the promises of God. Like the questions "What about Paul's Thorn" and "What About Job", we often are tempted to look at God's word through the lens of our experiences instead of letting God's word define our experiences. He is faithful to His promises. If His word says that He heals all of our diseases, we ought to believe that. Instead, many believe promises like that must not be true or must not apply physically since "so and so" prayed and didn't see healing manifest. We need to walk by faith, not by sight. We need to believe God instead of Bob. Once we can give 0% credibility to our negative experiences, and 100% credibility to God's word, we will see His promises manifest in our lives.