I have actually done it twice! First time, part of a barn wall fell down in a bad storm where I was renting. I was walking around to see how bad it was and didn't notice all the nails sticking straight up out of the fallen wall. I didn't even feel it, but could not lift my foot to take the next step. It was a very strange sensation. That one didn't get infected either!I did the same thing when i was a teen. Never felt the nail until my shoe filled up with liquid... blood!