It's just a game. Yet when a win or loss carries financial repercussions, the once-enjoyable pastime can quickly become an overwhelming addiction.
Experts say sports gambling problems usually begin with a March Madness bracket pool or a Super Bowl bet.
For some it's just good office fun and a $5 wager, but for others the rush of winning sparks a need for more gambling with bigger stakes.
Not only is such betting illegal, but experts say it can quickly wreak havoc on jobs, families and finances.
Tim Otteman, a professor at Central Michigan University and former gambler who now spends his time researching sports and gambling, cites statistics from the NCAA that roughly 1 in 10 Americans filled out a tournament bracket.
Yet, "out of nearly 6 million submissions to ESPN.com, two participants correctly picked all four Final Four teams," according to the National Council on Problem Gambling's website. "For those who have gambled real dollars, a loss affects both their team spirit and their bank account."
The Council notes that there are more than 3 million gambling addicts in the US who began by exhibiting warning signs like "never admits to losing," "borrows excessive money from friends," "has multiple credit cards," and "more irritable, restless and isolative than usual."
Otteman notes that most men and women can gamble responsibly, plunking down a few dollars to participate in an office pool and moving on after the championship game with no hard feelings.
However, he still warns of the "clear continuum of activity."
"The bottom line is that no one ends up with a sports gambling problem without making his or her first bet," he said. "And frequently that first wager is filling out an NCAA tournament bracket."
The growing concern is that teens and college students are becoming more involved in gambling, thanks to a variety of online betting options.
Some kids never touch it, while others use it a few times a year and some just do it socially. Others use it constantly, turning into kids who find it controls their lives and causes them to lose friends, family members, jobs, and money.
"Like alcoholics," Dailey writes, "gambling addicts are often secretive, irritable and unable to cut back."
In fact, a new study from the Research Institute on Addiction at the University at Buffalo in New York shows that 3.5 percent of Americans are problem gamblers — compared to the 1.8 percent of Americans who are alcohol dependant.
Frequent gambling among men was at 28 percent, while women were at 13 percent.
For anyone worried that their buzz from March Madness might be getting out of control, a new web-based test from Harvard Medical School's Division on Addictions allows people to evaluate the level of their gambling problem.