...and it would be a crazy happy world. Truth would only be a matter of one's imagination. Fallacies would be the only consistencies and no professor would be smug. People would be generally confused and disoriented and no one would bat an eyelid when sold 5 oranges after paying for 6. It would be a chaotic world with its unsure zombie like citizens walking around on crazy Mobius strip shaped roads. The principle of mutually assured destruction would cease to exist because no one would be sure if 10,000 is greater than 1. Hence countries would stage preemptive nuclear strikes and finish off this stumbling, hobbling world and the rest of the universe wouldn't give a damn.
But there would be advantages, definitely. If somebody asks you what would you do if you had a million dollars, you can simply say that you don't even need a million dollars. And yes, quantum electrodynamics would probably have a believable premise.