This is an anecdote that I read while reading The 48 Laws of Power. It comes from the Essays in Idleness, Kenko, Japan, 14th Century.
A man who was famous as a tree climber was guiding someone in climbing a tall tree. He ordered the man to cut the top branches, and, during this time, when the man seemed to be in great danger, the expert said nothing. Only when the man was coming down and had reached the height of the eaves did the expert call out, "Be careful! Watch your step coming down!" I asked him, "Why did you say that? At that height he could jump the rest of the way if he chose." "That's the point," said the expert. "As long as the man was up at a dizzy height and the branches were threatening to break, he himself was so afraid I said nothing. Mistakes are always made when people get to the easy places."