We all know the meme, but most of the time it's referenced about someone shitty saying something you already agree with. What I wanna hear about is a time when someone who you broadly disagree with actually gave you some kind of new insight about something - even if you didn't end up coming around to their point of view. Maybe they gave you a piece of a puzzle that you were missing, but then you built on that in a completely different way.

Doesn't have to actually be "the worst person you know," interpret it however you like.