Learning something hard changes how you think, but nobody hands you a certificate for that part.

The lasting effect of a difficult subject is rarely the content. What stays is a new habit of mind: the way maths makes you check whether a number is reasonable, the way a language makes you notice how your own sentences work, the way a sport teaches you to wait before reacting. None of that appears on a transcript.

Work out what a subject has changed about how you approach a problem, not just what you can recite. Write a line or two about it. When it comes to explaining yourself in an interview, that answer is worth more than a grade.