[neat insight from Dave]
The Apostle Peter was a fisherman. Do you think he ever fell out of a boat? What would his experience teach him about stepping outside of a boat?
And yet, in spite of past experiences, when Jesus called to him, he got up and stepped outside the boat and walked on water.
If God is in the equation, we can never assume our past experiences will define the outcome.
Jesus addressed this after the famous "camel passing through the eye of a needle" discussion. Here was something which common sense, if not experience, would tell us cannot be done.
"With men this is impossible; but with God all things are possible." Matthew 19:26