When people don’t fill out forms, they often use the excuse that it’s too much work. Consider how to encourage them with negative or positive incentives. The IRS appears to have entirely solved this problem, too. Once again, the key comes from the close relationship with the criminal justice system that the IRS enjoys. Willful failure to file your taxes can result in criminal charges. However, the IRS also has an elaborate and complicated set of financial penalties available for people who fail to file their taxes or pay them in a timely manner.

On the other hand, the IRS offers rewards too. As many people overpay taxes during the year, customers who are unsure about their taxes often fill them out early in the hopes of “winning” a refund of their overpayment. This helps keep users interested. —Peter Seebach —The cranky user: Bad design can be so taxing (IBM)