A long time ago, I was told this in joke form. Something like: "Why do programmers always confuse Halloween with Christmas?". When telling this joke you have to WRITE the punchline down on a piece of paper as in your post title, or people won't get it.

The person who told me this joke was Ward Christensen, the guy who invented the XModem file transfer protocol. Yes, I know....insert generic "old guy" remark here.