Peter exhibited great faith when he stepped out on the water. But then he allowed his immediate surroundings to hinder his walk.
Peter's faith began with a tremendous bold step, but it required a level of focus that he wasn't used to.
Follow through.
That was the problem. Those pesky waves, and the way he usually thought about and experienced water---not something that generally supports your feet.
We all know what Peter should have done. Keep his eyes on the Lord, not the waves! That's easy for us to say.
But how many of us have ever stepped out of the boat? I didn't notice any of the other disciples playing follow the leader with Peter...