Nerdy Maths post incoming...
At the moment I'm doing 22 GCSE exams in the space of one month.
I just had my Maths Paper 1 yesterday. Not that it was hard, but one of the questions had a tree and next to it a house. A girl looks at the top of it from the bottom, and then from a balcony, and you've got to find how tall the house is, the angles of elevation depending on whether the girl is on the balcony or on the ground, etc.
It was a relatively easy Sine/Cosine/Tangent question, but they neglected to mention if the tree was perpendicular to the ground or not, and while everyone else assumed it was, I got paranoid and didn't, so I spent ages lengthening lines and using formulae which didn't even have to do with the question to see how I can answer it, until there were a few minutes left and out of panic I decided that there was no other way; I had to assume that the tree was perpendicular to the ground. I did and everything was easy from there. Still, not specifying that is a big sign of unprofessionalism, in my opinion.
A similar thing happened in my Maths mock exam. The paper had a question where a stone slab was resting diagonally on a wall and we had to find the angle with which it was resting on the wall and stuff... Another easy Sin/Cos/Tan question.
However, he didn't mention if it was a rectangular stone slab or if it had an irregular shape, so again, while everyone else assumed it was, I didn't want to risk it and spent a good 20 minutes on that one question alone trying to figure it out. Seriously, our Maths teacher is one of the first to warn us to never assume what we can't prove, and then he forgets to specify something which wasted my time and made me leave a big part of the paper out. I would've skipped the question and gone back to it later but because we're writing on a booklet and not the actual paper, once we start a question we're not allowed to stop halfway through.
As much as I like Maths, I hate Maths exams because I always have to rush through them or not even manage to do all of them because the people who made the questions are such...
...I'd better stop there.
/rant.