A long time ago (pre-internet) I heard a normal person can learn to juggle in 1 day. It took me 2 days, but I learned to juggle 3 balls. But soon I realized what you said, the need for a consistent toss. Not sure of the reason, but I always make some errors with physical movements, they are never perfect. Even with typing, no matter how much I exercise, I cannot get bellow ~3% errors. Wondering if this is some kind of genetic effect, and how many ppl have similar issues.