I find it fascinating that it uses a 2-9 scale to grade difficulty.

The rating is described as a rating "1 - 10"

But every trick is actually graded 2 to 9. ( https://libraryofjuggling.com/TricksByDifficulty.html )

Presumably no-one ever wanted to define a grade 1, just in case an easier one was discovered, and similarly for 10.

Juggling is one of hobbies with the highest ratios of being able to impress random people versus the actual effort you have to put in, and I generally find I never forget 3-ball stuff I learned as a kid. It's also as good as a long walk for getting you out of your head when needed.

Shout out to anyone that remembers the Mushy Pea juggling shop in Manchester many years ago, where I learned all sorts of circus skills.