If you haven't read David Foster Wallace's 2005 commencement address at Kenyon, you should. It's humble and real and warm, and truly great. It's also very difficult to read. After his suicide, it's impossible not to hear the echoes of Wallace's internal conversation, the darkness and doubt and obsessive thoughts that he clearly struggled to get a handle on.
As I'm sure you guys know by now, it is extremely difficult to stay alert and attentive, instead of getting hypnotized by the constant monologue inside your own head (may be happening right now). 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 quote the mind being an excellent servant but a terrible master.
It's not technically available online, but you might be able to stumble across it in the depths of the Internet archives. Thanks, Dave.