The line comes from Dumb and Dumber, the 1994 American comedy film starring Jim Carrey and Jeff Daniels as Lloyd Christmas and Harry Dunne, two well meaning but hopelessly dim friends. Their road trip story is built on misunderstood situations and extreme overreactions to ordinary problems, which is why short lines from the film work so well out of context online. Clips like this one circulated on soundboards and in edited videos as a reaction to bad decisions, where the calm agreement to do something drastic sums up giving up on a sensible solution.