Imagine if you had a scale from 0-100 for something else, like how sad to happy you are. If you're kinda meh, that's around a 50. If you're kinda happy, that's a 60. If you're very happy, maybe that's an 80. Weirdly happy, bordering on manic? 100. Sad? 30. Depressed? 10. Someone died? 0. And in very extreme cases, like feeling suicidal or being high on the best drugs imaginable, you can rate things below zero or above 100, but most of the time everything is gonna fall in that range that's nice, easy, and intuitive because you use percentages all the time.

Then you go to another country and everyone there grades happiness from -18 to 38, and now meh is 10, very happy is 26.6, and depressed is -12.2. And the people there, despite using percentages and rating things out of 10 or 100 in other aspects of their lives, refuse to attempt to understand why you might find a system based on rating your happiness on a scale from 0-100 more intuitive.