Timing is an important facet of life. Timing is most important in photography, too. For example, a photographer photographing a sunset doesn't just arrive at a designated spot at sunset. He or she will arrive earlier in order to prepare the camera gear and to resolve any issues that a photographer can face when shooting outdoors.
Back to that timing concept in life -- the time for the punchline is not when the barber is in the act of trimming eyebrows with a pair of scissors.