"But Michael," you may say. "You're a cellist. His cello concerti are part of the canon, and we wouldn't have string quartets if it weren't for him."
First, don't say concerti; it's pretentious. Second, I'm grateful that he kept string quartets around long enough for someone better like Beethoven to come along and perfect the art, but that doesn't mean I need to listen to them. And third, 'bout those concertos:
C major moderato. Could it be more of a snore fest? I really don't understand why anyone ever performs this piece. What is there to like? I'm listening to it right now, and I can't hum any of it back to you. It's not even that flashy for the soloist. A great concerto should tell a hero's story. This hero sounds like he's chilling at a picnic.
There are so many, so much better concertos to choose from. Even if you're not feeling up to the gargantuan might that is the Dvorak concerto, there are very playable and magnificent concertos by Saint-Saëns and Elgar. Shostakovich has a brilliant one, and John Williams's concerto is a powerhouse. Why choose Haydn? Why?
People talk about how witty Haydn is. I don't think that music by itself can be witty. It can certainly be clever, but not witty without referencing something external of itself. A melody by itself can't be funny.
Case in point against Haydn, his "Surprise" symphony. It's only funny because people kept falling asleep while listening to his music. Yeah.