Every day, every month, you go to work. You can't stop. If you stop - the pay stops too.
But with passive income, when you stop working, you carry on getting paid. Sure, it takes some effort - or existing assets, such as a spare room, a car, or capital - to get started, but if you take the time to build up a passive income base, it will just keep paying you over and over again.
Passive income gives you freedom - freedom to spend more time with your family, to travel, to play guitar or write that novel. Or you could spend the extra time setting up another source of passive income!