Here's the thing. When your exams have problems that require right answers for points, you can get it wrong. Very wrong. In less math-based coursework, you write a paper, give a presentation or do a group project. And as bad as that paper might be, it is not as easily deemed WRONG. It might be a really really bad paper, but chances are good that you'll probably still get a C. That's 75% right. In math, there are so many wrong answers and there is a single right answer (side bar: technically you can do proofs in multiple ways and there is a bit more creativity involved, but I would say this is a subset of work in applied math). This means, by law of large number, there's a decent sized chance that you'll get the answer totally wrong. And with an X number of problems on an exam, you could even get all X of them wrong. That's not a C, that's a 0. Maybe a 15 if you showed some work.
This stinks. In my experience of both taking and teaching economics and math, instructors acknowledge the high likelihood for lower grades and curve heavily because of it. However, the fact that you got 15% of the total possible points on the exam is disheartening at best. Justification to quit math (chemistry/physics/engineering) at its worst. DON'T DO IT.
First of all there is an extreme shortage of students taking majoring in STEM (science, technology, engineering and math) in U.S. colleges, which Marginal Revolution has pessimistically highlighted relative to tuition and which I have blogged about. Secondly, the process of learning mathematical skills through failure is irreplaceable. While throwing markers at the white board over a tough proof, banging your head against the keyboard trying to find the error in your programming, using up pages and pages of graph paper to finish a problem set, you actually learn SO much. It's not until you get your hands dirty and try to actually solve problems that you really understand what's going on. And when that clicks, when you do solve for the right x (or at least the same one as your study group), it is worth celebrating with a huge nerdy fist pump. Because it is so insanely frustrating when you can't quite get it, celebrate profusely when you do.
Additionally, a university is an excellent place to learn technical skills. As fascinating as humanities and other non-mathematical subject areas are (and while I am of course partial to the math-minded, I did attend a liberal arts college and nearly major in Philosophy), much of this material can actually be learned outside of the university setting through work experience and good reading. In contrast, it is quite difficult to self-teach microeconomic theory. Other smarter people have given similar advice on the importance of technical skills in development here and in graduate school here.
So, take those cool art and language classes, and learn how to think critically and write a good paper, but take math too. And don't give up when it gets hard.
(Yes, the Barbie photo is sarcastic. And yes, I've used it before).