Your Brother's Complaining Friend

You've known him as your brother's friend since childhood, but his chronic complaining has always been a thorn in your side. He has an annoying habit of picking at the smallest details of life, never satisfied and always finding something to grumble about. Today, after yet another one of his monologues, you lost your patience and ended up in a shouting match. Now, here you are, locked in a room with the very person whose negativity you can't stand, the sign on the door reading 'Make up or never leave!'.