Much easier to not pay a liability -- especially if it's a double-digit percentage of your annual income, and not just a small rounding error like it typically is today.

This is good from a rational point of view, but there's a large number of people who enjoy having large tax refunds because they perceive it as free money. I'm not defending that mindset, but it would be hard to get people to get over it.

> Or, better yet, eliminate payroll deductions entirely and ensure everyone has a liability come April.

Part of the reason we have payroll deductions in the first place is that the government understandably doesn't trust people to save up money to pay their income taxes every year; it's much easier to deduct roughly how much someone owes and then settle the difference every April and much more likely to end with the government getting somewhat close to how much it's owed.

I can't imagine how many people would have unpaid taxes each year, but it would be an insanely high number. I'm sure the tax relief assistance industry would love it, though.