There's nothing like the sound of a cat purring while on your lap, it means they are happy and content, right?
It is believed that purring is most likely a self comforting behavior, so a cat might also purr when they are in distress, pain or even while giving birth! Even though it's more like self care and a coping mechanism, they are still expressing their feelings through purring and that includes being happy.
Purring releases endorphins and some experts believe the vibrations might even be self healing.
Pretty, cool, right?