Beware these 5 terrible tax surprises

You spent the last 40 years fattening the U.S. Treasury thanks to those dang Social Security taxes that came out of every paycheck. Now you're retiring, and it's time to get your tax money back, free and clear, right?

Well, maybe. Maybe not.

Generally, if Social Security benefits are your only income, your benefits are not taxable. But if you collect Social Security plus other income, as much as 85 percent of those government checks could be subject to tax. To figure out just how much in taxes your Social Security might cost you, you'll have to do some calculating using the work sheet found in your tax Form 1040 or 1040a.

If you discover that you will owe taxes on some of your Social Security benefits, there are two ways to deal with them. You can make estimated tax payments on the government check amounts. Or you can have federal income tax withheld from your benefits by completing Form W-4V, Voluntary Withholding Request, and filing it with the Social Security Administration.