My daughter recently came home with an 86 on her science test (gasp!). She studied for it and at least from my point of view she seemed to make a legitimate effort at preparing. She was disappointed that her grade was not an A but there were no tears and she was confident that she would do better next time. I am satisfied and think she did well. Of course, I want her to strive for excellence but not to the point where it causes an ulcer.
This ability to bounce back is a better trait to have than good study habits. In the world beyond academia, grades are rare and life is mostly pass or fail. When was the last time your boss handed you back a report you had written and said, "I'd give this about a 76%. It is passing but not by much." While there may be a few managers like this, most of work-life is either pass or fall. Did you get the sale or did you not get the sale? It doesn't matter that you prepared all week and did a great presentation hitting all the key points for the client. Did you get the sale or did you not get the sale?