Luck happens when Oppurtunity meets Preparation

During the shooting of a movie, a scene came up where the hero had to jump from the top of a building into a pool of water and beat a gang of villains. As the scene was being shot, the hero ran up to the edge of the building and suddenly stopped. Perplexed, the director paused filming and asked the hero why he stopped. The hero replied that it was nothing and asked to redo the shot.

The sequence repeated 4 more times. By now, the director understood that the hero was never gonna make the jump which was utterly crucial to the movie. He then inquired if anyone was prepared to do the jump. A lean guy from the gang of people supposed to be beaten up by the hero volunteered. He successfully made the jump and the movie was shot without any further hiccups.

The movie was a Chinese movie. The hero who hesitated to jump was the original martial arts star Bruce Lee. The guy made the jump was Jackie Chan, currently Asia's highest paid star.