Now, here's the thing:
My first FIL used to get all kinds of bent about tax refunds. His take was that you're lending the government money interest-free. MY take is that those few hundred buck a month would get pissed away frivolously and not saved. But when you get a check for $10,000, THAT is real money and you'll put it in savings or make a major purchase with it (mine will go into savings).
Even if your refund is only a thousand or two, it's still a big fat check vs. the hundred or two you'd have kept each month and frittered away. Currently anyone could shave at least $50 off their monthly expenditures, and stick it in savings. But nobody does that - we spend what we make.
So why does it make any sense at all to get right on the dollar with your taxes and not overpay? Sort of like an enforced savings account.