I'm sure I'm not the only one who has experienced this.

Teacher: We've got a HUGE f*cking test coming up.
studentA: Will it be concepts or details?
Teacher: mainly concepts, a few details, but only those that we REALLY stressed in lecture.
Me: (whew!)
************
((1 week later))
studentA: so dude, you read for the test?
Me: totally, I know the concepts COLD.
Teacher: Ok, here's your exams. Good luck!!
Me: I am totally prepared for this, having spent a large amount of time studying what the teacher told us to study.
(((looks at test))))
Test: details, details, details, details, details, details, details, details, details, details, details, details, details, details.
Me: NOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO OOOOOOOOOOOOOOOOOOOOOOOOO
Teacher: MUAHAHAHAHAHAHAHAHA