Whatever the subject matter, these beliefs and behavior are usually based on an unquestioning acceptance of traditions passed down through the generations. The problem, of course, is that tradition by itself is no criterion of reasonableness.
When I was in high school, two of the things that could get me going on a rant were the uselessness and irrationality of pennies and the fact that we don't include sales taxes in our prices. Apparently, others are starting to speak out too:
And if you're worried that this would be "unpatriotic," suck it, it's been done before:
Now, before you go rid the world of pennies, be careful where you try to dispose of them: