For me, coffee blows my mind. Somebody was like "yeah this fruit is fine but what if we take the pits, roast them, grind them into a powder, and then pour hot water through them?"
Crazy genius that the world should give thanks for.
It's olives that get me. I want to salute the guy who took an inedibly bitter fruit and thought "I know, if I bury these and leave them soaking in caustic soda for six months, they'll be delicious". I mean what kind of a leap is that?!