What instrument is the hardest to play well?

[Anonymous]

Another vote for French horn. Played the trumpet for years and picked up French horn to fill a need and…yikes. That’s a hard instrument to control. Can’t play any of them now as my embouchure is well and truly shot from years of neglect. But I could bang out a few notes on a piano and probably a violin too even though it’s been 30 years since I’ve played either regularly.