practicality

If it helps, you don't really have to be good at much of anything to have a job in graphic design - and studying it in college won't necessarily teach you anything or make you more skilled. Half of it is knowing the skills to make a slick-looking finished product - and that alone will never be enough to create a great work with. The other half is taste and sensibilities - Understanding not the rigors of color theory and the grid and such (these fall under the taught skills) but understanding what looks good, what feels right, what appeals to people.
I remember how during what should've been my senior year of art school, a friend of mine who was about to graduate replied to my expression of frustration with the school by asking me, "Why don't you quit? I wish I'd quit." It took me several more months of classes to realize that she was right.

Science, with objectivity and truth, teaches you the analytical attitude. I have no head for facts and equations and specific knowledge in an academic field, but I think all the required sciences I took in high school gave me a more general understanding that still helps me today - the ability to acquire knowledge through a controlled process, to experimentally verify, to look inside a thing and see how it works.
I think there are a lot of things you can study in college that do not prepare you for anything you're likely to do in adult, professional life. I think that science, whatever field, will never be like that.