I'm living in one of those other countries. My employer removes tax from my salary every month. But they just follow some guidelines. Our tax system is quite co

I'm living in one of those other countries. My employer removes tax from my salary every month. But they just follow some guidelines. Our tax system is quite complex and my employer doesn't have enough information to know how much to send to the IRS. They can't even make a decent estimate, actually. So we still need to file a tax report every year. The guidelines and the system are set up so that most people pay too much tax in general. We do get our tax reports already filled-in by the IRS though. It's getting better each year. For now most people just check everything is there and whether it is correct and just sign and send (everything is done digitally of course).