Everybody has to fill their car with gas at the pump.

Notice how you grip that nozzle; you’re using a hammer grip. Interestingly enough, it’s the same grip the first servers in the world use. Why?

It naturally allows your arm to rotate, or pronate, as it swings up to the ball. Pronation adds snap: snap adds racket head speed.

It provides an angled racket face to the ball which intensifies spin prodction when desired (slice).

It provides an open string face to the ball which provides an upward trajectory. This is necessary to hit a "kick" delivery.

If you are not currently using a hammer-style grip, it won’t prevent you from serving adequately. However, you’ll never have the speed and spin of the top-knotch servers until you convert to the hammer grip.

Remember that the next time you fill up.