Why the heck do we curse?

What is the purpose of using a curse word? Is it to get attention? Is it to create an emphasis that politer words cannot match? Here's a fascinating article on cursing. It talks about the why curse words don't quite work the same way syntactically as other words - "swat the stupid cat" works just as well as "swat the cat, which is stupid" but "swat the f***g cat" doesn't work as "swat the cat which is f***g." It talks about the role of religion in the evolution of curse words. It talks about the various reasons one might have for swearing. And it discusses how the brain reacts to swear words. But take a few minutes and read the darned thing yourself.