Twenty years after my own graduation, I have come gradually to understand that the liberal arts cliché about teaching you how to think is actually shorthand for a much deeper, more serious idea: learning how to think really means learning how to exercise some control over how and what you think. It means being conscious and aware enough to choose what you pay attention to and to choose how you construct meaning from experience. Because if you cannot exercise this kind of choice in adult life, you will be totally hosed. Think of the old cliché about “the mind being an excellent servant but a terrible master”.
This, like many clichés, so lame and unexciting on the surface, actually expresses a great and terrible truth. It is not the least bit coincidental that adults who commit suicide with firearms almost always shoot themselves in the head. They shoot the terrible master. And the truth is that most of these suicides are actually dead long before they pull the trigger."
— David Foster Wallace