Perhaps Andre meant hardest to master/do smoothly, which in my opinion should be the meaning,
for instance almost anyone on can learn how to do ladder escape, rancid milk, or other tricks, but it takes much practice to be able to do them smoothly and beautifully.
I was going to answer -“Whichever trick I happen to be having difficulty learning.” - but this gets much more at the long-term difficulty of any pursuit - not just pulling it off, but pulling it off, as you said, smoothly and beautifully.
What if the trick you’re having difficulty with is the man on the trapeze? By your statement, that would make it the hardest 1A trick, right? Compared to the “trapeze”, double or nothing, triple or nothing - heck, even quadruple or nothing! - should be a cinch!
The hardness of a trick is pretty dependent on the person trying to learn it. I agree with you there. That is a solid definition for difficulty. The thing is, though, you can’t extend that definition and say that the hardest trick is the one you had the most trouble with until you’ve learned all the tricks.
In my opinion, the hardest trick to LEARN, is called the throw. Nobody has ever mastered a throw IMO.
The hardest trick to do varies from person to person. I have problems with whips, so I can’t do a lot of the higher leveled tricks smoothly.
The hardest trick ever would have to be No Noised Nonesense.
It consists of many elements, which include breakaway, double or nothing, lighting the string on fire, replacing the string while the yoyo is in mid air, laceration, suicide, suicide, kick a kitten, fly away dismopunt, club a seal. Try it, harder than it sounds on one throw.