In the UK, for example, most employees do not have to file a tax return. The HMRC files it for them and sends them a letter every tax year with their calculation. It even comes with a nice chart to see how much tax you've paid and where it went to (https://secure.i.telegraph.co.uk/multimedia/archive/02871/ta...).
The tax brackets are also very straightfoward and everyone knows which bracket they are in. The same is true with tax on product prices. Everyone knows the tax rate on items because it's a simple number and there's a lot of public discussion whenever politicians decide on reducing/increasing it. If you ask anyone in the UK (or any other country other than the US with VAT) what the current VAT rate is, they will be able to tell you. Good luck getting an answer to such a question from someone in the US; you just pay what the cashier tells you to as VAT depends on so many factors.