I think @Ensign_Crab is talking about how other countries like the UK and France do things, where you don't have to file. The government sends you a letter that says "you owe X" or "your refund is Y", and if there's anything that's not reported in there or things that are wrong, then you file that with the government and they go "oh, OK, here's your adjusted amount". Simple forms are often not "simple", especially with our arcane, convoluted tax code.
funny thing is we even have the perfect form for it. if the irs whould send us a 1040x with the left hand side filled out we could just sign it and move on or make changes to the right side and sign it.