Good advice?

In the course of emailing a student worrying about her grade for the semester, I wrote something that I think is actually pretty good:

That said, to paraphrase Lyndon Johnson when describing the value of the vice-presidency, GPA is worth a warm bucket of [spit]. I know it is something one worries about when in college, because it is the only barometer one has at the time, but really, it is a very poor predictor of future success. In whatever career you decide to pursue, people will judge you based on the interactions you have with them -- within 5 minutes of meeting you, people of importance will know if you are an idiot or not -- and that judgment is really all that matters. I'm not saying don't try hard to get good grades, but I am saying that it is far more important that you understand the material and, in a broader, why-am-I-in-college-sense, figure out what really gets you intellectually excited. People who don't like their jobs don't feel that way because their job is mentally hard, but rather because it doesn't engage their brain. Likewise, people who do like their jobs don't feel that way because it is as easy as high school, but rather because they're not staring at the clock every day waiting for it to hit quitting time.