Post-it notes. The world would be in chaos without them. Nobody would remember anything. Nobody would be able to turn their office walls into superhero murals. Nobody would be able to leave passive-aggressive messages on the doors of communal refrigerators. And nobody would be able to have the sort of epic Post-it note battle that recently took place in New York.
Post-it manufacturer 3M also joined the war by providing free ammunition (i.e Post-it notes!)
Workers stayed late with beer and pizza to create the spectacular finale, and fellas from Spectacle Studio later posted this video
Unfortunately, the battle was ended by building managers who ordered all participants to have everything taken down by the weekend.