I've never gotten less than a 4/10 in an exam, so I don't think there's any story to share. I always had pretty good marks
One funny thing that happened me once, I got a 10 in Geography without having studied absolutely anything, and when the professor hands me the exam, she says "Great job, I'm sure you studied a lot for this test, you're a very hard-working student" or something like that, I almost laughed in her face and told her I hadn't studied.