Mastery Grades

Just a small thought. In elementary school in Canada we would get two grades on our report cards. First; a letter grade, A B C D or R (Remedial), and also a grade on various other aspects of our workmanship in class. These would go E (Excellent), G (Good), S (Satisfactory), or N (Needs Improvement), So naturally whenever I, and many other people, see S as a grade, I think I did a bad job. Can this letter be changed to something else, or simply A B C D or F?