Some actions are described as "perverse". These are when you chose to do something you know is wrong—morally or otherwise—at least in part because it's wrong. A perverse action might be breaking a rule just for the sake of breaking it. Or doing something stupid just for the sake of doing something stupid.

One example is from Saint Augustine's Confessions—he describes stealing some pears just because he wanted to do something evil. In a recent television show a woman is questioned about an affair she had, she responds, "I did it because it was wrong." A 4-year-old is told not to drop cereal on the floor or there will be serious consequences—she gets a funny gleam in her eye and then sends the whole bowl flying.

Please tell a story of a perverse decision you made or watch someone else make. This can be as long as you want. 

By providing an answer, you are giving me permission to use it in my writing and my talks (but of course, I'll keep it anonymous).