Not understanding a miracle: How often have I done this?

In Mark 6:40-52, there is an amazing juxtaposition of two stories. First, Jesus feeds a multitude of people, at least five thousand, using two loaves to give everyone bread. Second, he walks on the sea and calms a storm. The really amazing part is in verse 52, which says "for they did not understand about the loaves, but their hearts were hardened." (ESV). The twelve disciples had seen, even helped out, with the first miracle, but were not expecting the second. How many times have I done this?