I was watching Jeopardy! the other day and neither I nor any of the contestants could come up with the answer for the clue: What type of simple machine is a doorknob? Turns out, it's a wheel and axle.
That got me thinking how I might be lucky to name even four of the seven types of simple machines but I could easily remember all seven of the dirty words you can't say on TV. And I don't think it's just me. How many of us forget the basics but can remember irrelevancies in great detail?