Do you want to be confused and frustrated? Endlessly mocked by the shortcomings of your sad neuro-muscular insufficiencies? Then do I have a thing for you!
It's GREAT! You'll juggle for 20 perfect catches and then throw one ball directly into an other. Then you'll start again and fail immediately! Next up, 12 catches before the ball just bounces off your hand.
In SO many other activities one gets better and better in an easily seen manner. You practice - you get better.
I suppose in some subtle sense it's the same with juggling. But the externalities are SO different. Here's an analogy. You get up from the kichen table, walk 5 beautiful steps and then fall down. You get up and immediately fall down again. Then you get up and walk all the way to the front door and the end of your sidewalk. And then fall down.
THIS ISN'T RIGHT!! Once you "get" it it should be all done. 10 or 100 - no difference. But that's SO not the way it is with these innocent looking but clearly spawn of the devil juggling balls.