Economics: "Humans only value things monetarily."
Sociology: "Uh, I don't..."
Economics: "Humans are always rational and value is calculated by complex internal calculus."
Sociology: "Uhhh, Psy, can you help?" Psychology: "That's not how humans..." Economics: "ALSO MY SYSTEM WILL GROW EXPONENTIALLY FOREVER!!"
Physics: *drops teacup*

(Credit: source unknown)