But Iceland errs on the side of under-withholding, if they don't know what your income is going to be. As a result, come tax time, most people get a letter saying "you owe us 60,000isk"[1], and they pay it back as extra money garnished from their wages over the next year.
The Australian government errs on the side of over-withholding, which sounds bad, but it's more like a mandatory saving scheme. Most people discover the tax office has over-charged them by at least $800 over the course of the year, and you get it paid to you in a lump sum after they process your tax return. After deductions are filed, it's not unheard of for people to get 4-6k back.
As a result, for most people in Australia, tax season has a bit of a party atmosphere to it. You'll find people talking about what they're going to buy with their return, and there are sometimes tax season sales on things like TV's etc.
It's a really great example of a small and seemingly unrelated implementation detail making or breaking the whole experience.
[1] about $600, figure example only :P