I'm going to assume the actual statement "Good students are good at everything" is a quote that is, at best, rather out of context. It's patent garbage; I often take classes (and advise others to take classes) in things I know I'm no good at, either to advance from "Useless" to "OK", or just because it's something I enjoy. My art skills are truly awful and I'll never get top marks, but it wouldn't stop my taking an elective, because I'd like to be better and enjoy the area.
People who constantly get top marks in everything are, to me, suspicious. Mostly anyone who's smart can pick a syllabus they'll ace - but will they gain anything from it? Now, if they're getting constantly low marks, or random mark disparities in seemingly related areas, that might be a legitimate concern, but to blanket it as "Good students are good at everything" is just bizarre.
I have a hard time believing any programmer has difficulty with Macroeconomics. A C in a course like that says 'lazy and willing to accept mediocrity'.
You're actually taking the quote out of context. Getting a C in an art class is different from getting a C in macroeconomics. "Everything" doesn't refer to, say, athletic ability, I'm sure. There's some limitation to the set of abilities involved, centered around mental abilities, and art skills might be outside that limit, in the quotee's mind.
I mean, it's really easy to imagine a "good student" branching out, taking an art class, and getting a C, but it's hard to imagine a "good student" branching out, trying macroeconomics, and struggling.
I certainly can imagine a curious student taking macroeconomics and get so utterly bored and annoyed that he gets a C. In my case the course was "Entrepreneurship" and while the course itself was (mostly) interesting and inspiring, the test at the end was stupid and I recieved a C (well, something equivalent in Germany).
Now i'm thinking whether look for a job is the right way or whether I should rather look for a cofounder.
However, it's also easy to imagine someone taking a class and discovering he simply wasn't interested in it (or thought it was complete bull), only finishing the class to get the credit. It is silly to judge people by an occasional C amidst A's.
People who constantly get top marks in everything are, to me, suspicious. Mostly anyone who's smart can pick a syllabus they'll ace - but will they gain anything from it? Now, if they're getting constantly low marks, or random mark disparities in seemingly related areas, that might be a legitimate concern, but to blanket it as "Good students are good at everything" is just bizarre.