Aside from wanting to take some pressure off myself, I maintain that grades really aren't that important because I value education for more than its spot on my résumé. The reason I'm in college isn't to get a good job later. I would be here even if I knew I would never, ever get a job, because I think that college is worth something much more important than some money later on. I think that education is about better knowing yourself, better knowing the world around you, and attempting to figure out your place in the world. Understanding reality and your role in it ("Knowing thyself," as the ancient Greeks said), is infinitely more valuable than any material consequences of a diploma. Education is about self-improvement, not about the number of zeros on the end of a paycheck.
With this in mind, I think that grades start to lose their novelty. By valuing education for its personal return instead of its financial return, grades become less of a statement on the future and more of a (mostly) inconsequential part of knowing thyself. None of this is to say that it isn't important to work hard in school, which will often produce good grades, as working hard is part of improving yourself. What this means is that there is no need to get in a huff about a disappointing grade here or there: it isn't a comment on self-value, and it isn't a comment on projected success out in "the real world" (as opposed to this world, the fake one).
Grades have their place. They're a necessary part of education. What they aren't a necessary part of is self-esteem. They don't really matter because they don't define us: what defines us is the changes education makes within us. So maybe I got a B or a C on that last exam, but am I better overall for having taken the class? The answer is usually yes. And that is what makes education worthwhile. Forget the grades, forget the jobs, and just try to become a better person, enjoying the ridiculous luxury that education is.