while photocopying one day, i looked at the copies that came out of the copier and tried to compare it to what i was holding in my hand. it took me, embarrassingly, more than several moments to realise that the reason they did not match was because what i was copying was still in the machine and what i was holding was the subsequent pages of the same document.
in my defense, it was probably the 2561st piece of paper i was copying, AND, the document was in arabic!