Well I remember another thing. It is from a school.
I had this brainfucked teacher for IT. She didn't even know how to write in pascal or pronounce "boolean". One day we had an exam on computers and she dug up from God knows where these DOS programs that was made a decade ago for IT students to test their knowledge and shit.
I didn't perform well, because honestly - it was pathetic (and too old to understand) so at the end of it, the program crashed. Teacher, before the exam, said that if we close the window BEFORE showing to her the result, we'll get a 2 (10 score scale). So yeah, my program crashed.
But then I thought - she's stupid, maybe I can deceive her. And quickly shown her the fake error message through the CMD and said that these programs usually leave logs!, she told me to find them.
She believed and went away. I found some old IE cookies, copied some of it and changed a bit to say my name and the grade I got.
Of course it looked to her so bad-ass that she believed me and wrote the grade down.
This is just one of the better wins with that retarded teacher xD