Well if the student is aiming for the best, they have every right to be disappointed with an 8. An 8 is no longer the best grade, for there is a superior grade above it. Those who are truly aiming for the top in any particular subject (or all of them) will be expecting 9s, and can definitely be dissatisfied with an 8, especially if they exerted an immense amount of effort into trying to attain it. People with extremely high standards can be a little crestfallen with an 8, it is understandable.