To fear God is to revere Him. Unfortunately, humans like to revere themselves. They like to think that they are in charge. They try to make God in their image (as if they created Him).
Instead of fearing Him, they reduce the almighty to a "magical genie in the sky". Simply rub the lamp (pray) and He'll jump to do their bidding (do this for me, give me that). When things are bad they rub the lamp and demand He respond, but when things are going good, they no longer need Him and the "lamp" goes back on the shelf. And, if God refuses to grant them their wish, they simply shrug and say He doesn't exist.

Those who truly know God will fear (revere) Him with joy and gladness.