Is Struggle Valuable?

One of my logic students asked me after taking my final, "Why do you make this so difficult?" On the one hand, I'm not the one making this difficult, it just is. It's tricky stuff by nature.

But that being said, I do give a very hard final. I have pedagogical reasons for it, but what I am wondering about is a possible response to my student -- "Making it difficult is what makes it valuable."

This seems reasonable at first glance. But is it? Is there an intrinsic value to struggle? It is cliche that nothing worth having comes easy. But is this the theological basis of the Protestant work ethic sneaking in? Is it just macho "no pain, no gain" nonsense? Is something intrinsically more valuable because it was difficult to do or achieve?

If we say that every life should have some struggle, does that mean that any given struggle is valuable?