For me it’s time signatures in music. I grew up playing instruments, played in several orchestras, etc. But no matter how many times someone tries to explain time signatures to me, it makes no sense. I don’t understand why people place such importance on it. To me, notes have a pitch and a duration, maybe some dynamics. That’s it. I don’t understand why people try to needlessly complicate it. It doesn’t give you anything.
My wife will hear a song and go “Oh neat, it’s in 5/8.” And I’m like “How tf do you know that, and why does it matter?”
Time signatures fuck with my head too. I’m not a pianist, but I decided to try and learn Gabriel Faure’s Clair de Lune, which has always been one of my favorite pieces. My whole life I’ve heard it in my head as 4/4 , but to my surprise it’s in 3/4 and the left hand are actually 16th notes with the first one missing in each beat.