"You Made The Sandwich" is a callback to the popular subway meme in which someone makes their sandwich at subway and doesn't like it, even though they chose the ingredients. This phrase is used when someone is the cause of their own misfortune.
Guy 1: Ah man, I didn't study for that test and I got an F.
Guy 2: Dude, you made the sandwich.
Made is a word/meme that is sweeping the world wide web. It started off as you mad bro? But when that stopped effectively pissing people off it became uMadeBro? To which someone will instantly become enraged because they are either A) too stupid to understand what is meant by made or B) they know what made means and they are in fact quite made. It can be heard online over and over again by today's youth, You Made Bro?
Me: "Wow that guy just punched me square in the face!"
Friend: "You Made Bro?"
Me: "F*CKING HELLA MADE BRO"