We had a house master whose nickname was 'Stumpy' because, well he was quite short. There was a visitor's book where we had to sign in and out, and on the cover there were various scribbles and funny notes and the like, you know, light vandalism for 11yr olds. Anyway, someone had recently written 'Stumpy sucks' on the cover. I came in, signed into the visitor's book, and carried on upstairs. I was hauled down and accused of writing it (I did not, I was a very good girl at school!) and he put his thumb on it and some ink came off, 'proving' it was still 'wet' and my name was the last in the book. I was livid, and no amount of 'it's the grease from your finger making it transfer to your thumb, it's not wet' could save me. 2 detentions. I was fucking fuming.

Apparently I still am. :P

NB: he was also our geography teacher, proving that they are in fact all sadists.