Piece of Cake
Why? Why does that mean something is easy? MAKES NO SENSE!
Oh, I googled it, it makes sense now. Pieces of cake were the smallest and easiest prizes to get a silly festival competitions in the 1870s. Same origin as “cake walk.”
See, I’ve gone from faux-frustration to enlightenment in like 13 seconds thanks to the internet. Piece of Cake.