What do you lose your combo to? (Image unrelated)

Honestly, if I'm playing co-op then I definitely lose my combo to looking at the other's combos.

But when I'm playing solo, it's mostly those "surprise!" Small ahh notes. When they just come out of nowhere. Other than that maybe se sort of ladder notes, especially when they're flick notes. (I don't know if you call then ladder notes tbh. Just those when there'd 5 at once and each one is above the other or something.)