According to an old diary I found, 45 years ago I watched my father filling in a tax form. I noticed he was busy rubbing a candle over part of the form.
"Dad - what are you doing?"
"You see this box with 'Do not write in this space'? If I can't write in the box, no-one else is going to!"
I often wonder if this was an original idea of my father's or if he had seen it on some comedy show.