Not winning your NCAA bracket is one thing; unnecessarily losing your money to Uncle Sam is another.
That's effectively what happens to those who fail to utilize all possible tax deductions on their return and end up paying more than they owe. And when it comes to taxes, overpaying has a particular kind of sting.
Some are less obvious than others. For example, if you've cleaned out your closets, lost big in Las Vegas or even had a friend crash on your couch, you may be able to factor that in at tax time.
Here are some of those little-known tax deductions and credits that could lower your tax bill or increase the tax refund on your tax return.
It's not exactly a March Madness kind of victory, but it's certainly something.
— By CNBC's Jessica Dickler
Updated 5 April 2016
Originally posted 1 Feb. 2016
If your down-on-their-luck pal has been sleeping on your sofa for the past year and earned less than $4,000 in 2015 while you've been mostly supporting them, then you may be able to claim them as a dependent and deduct up to $4,000 on your federal return, even though you are not related.
Consider it a small token of appreciation for all of your hospitality.
(On the flipside, children supporting elderly parents can also use this deduction, even if they don't live together.)
All that bug juice and capture the flag paid off. Working parents can save more than $2,000 on their taxes just because they sent their kids to summer day camp, noted Lisa Greene-Lewis, a CPA and tax expert at TurboTax.
Thanks to the Child and Dependent Care Credit, you may receive a credit up to $1,050 of your expenses for one child under 13 and up to $2,100 for two or more children under 13.
The same goes for mini camps or day-care programs over winter break if you are working. But overnight camps, despite being a rite of passage for some, do not count toward the credit.
Most people organize their closets as part of their spring cleaning overhaul every year, but few think of the tax consequence.
Donating clothing, books, toys, furniture and kitchen goods all count toward your charitable contribution, as far as Uncle Sam is concerned. "That stuff adds up," noted Kathy Pickering, executive director of H&R Block's Tax Institute.
In order to get the deduction come April, keep a receipt of the donation, a note of the organization's name, and the date and fair market value of all non-cash goods, Pickering said.
For deductions of $250 or more, you must also have a written acknowledgment of the contribution that states you received nothing in exchange, she added.
Ease the pain of a losing streak by offsetting the tax on gambling winnings, suggested H&R Block's Pickering.
Since you do have to report your gambling winnings and will be taxed on the windfall, don't forget to also include your losses to reduce the total liability.
Of course, you can only offset winnings, not claim losses beyond that point. "You don't get to claim more than what you won," Pickering added.
For the 43 million Americans paying off some amount of student loan debt — this one's for you. Each year, you can deduct up to $2,500 of student loan interest, provided you have paid that much, according to TurboTax's Greene-Lewis.
But the Student Loan Interest Deduction is not for every student borrower; the amount of the deduction gradually decreases and phases out completely once your income reaches a certain level.
Did you brush up on a second language, graphic design or even social networking? Anyone who took an enrichment course to boost their job prospects can claim the Lifetime Learning Credit on their federal income-tax return.
It applies to tuition, enrollment fees and any required books or supplies for just about any post-secondary course.
"The rule of thumb is that it has to be at an eligible institution and to improve your job skills," according to H&R Block's Pickering.
The credit is 20 percent of the first $10,000 of eligible expenses to a maximum of $2,000.
Hiring a career coach, traveling to job interviews in faraway locations and fees to a job placement agency are costly. But any expenses related to job hunting can be deducted if they exceed 2 percent of your adjusted gross income, which is likely if you are unemployed and on the hunt for your next career opportunity.
Just keep in mind that a spiffy new interview suit or shoes won't count, noted TurboTax's Greene-Lewis.
Most people don't think much about all the time they spend in their car driving to sales calls, meetings or even OfficeMax, but those work-related miles add up.
Not counting the commute, drivers can deduct those trips at the federal rate of 57.5 cents per mile for 2015 and 54 cents per mile for 2016.
Approximately 60 million Americans use their cars for work-related trips, but 50 percent of them are not capturing that deduction, according to a survey by the mile-tracking app MileIQ.
The hard part is keeping track of it, noted Chuck Dietrich, MileIQ's co-founder and CEO. "The reason people don't do it is because recording all of this information is no small effort," he said, but "they never realize how much money they are leaving on the table."
Any energy-efficient solar, wind, or geothermal heat updates to your home could mean a big savings — and not just on your heating oil or electric bill. The federal Residential Renewable Energy Tax Credit is good for 30 percent of the cost with no limit, and that includes labor costs, installation and piping or wiring.
Homeowners can also claim other energy-efficiency improvements, including storm windows, HVACs and insulation, up to 10 percent of the cost with a $500 max.