“The crux is to keep always in mind that the reason you fill up a car with petrol is not so that you can get a high score on the fuel gauge. Your degree has, I hope, tanked you up with what you need to roar out of the garage and off into the wide world. Exams are only a measure of the thing; they are not the thing itself.”
I liked this bit from Drayton and Mackenzie, by Alexander Starritt.