If you go to the emergency room in the United States, what brought you there is most likely a sprain or strain, a stomachache, or a cold-type-thing that seems unusually severe.
Either that, or it's an injury that may or may not be a broken bone but wow-wee does it hurt. And it's getting swollen. Better go in just in case.
Then, after an average 28-minute wait, the ER doctor will tell you that it's just a contusion, another word for a really bad bruise. Then he'll charge you three times more than your family doctor—or thousands of dollars, if you're uninsured. In the Northeast, this was the most common thing that happened in emergency rooms in 2011.