That's one of the scenes I dislike the most, though I think Damon (Matt Damon!) did a great job acting it. It was a set-up scene.
We make fun of horror movie writing when the scantily clad lass walks trembling into the dark bloody room only to be karate chopped with a machete as lame and predictable, I think this is similar here (weirdly) - they set up the twat preppy smart ass and then Damon's so smart to know the actual books and quotations - it ends with him showing physicality - his "blue collar Bostonian" toughness. In a movie that's all about writing (as opposed to say "I know Kung Fu"), that seemed like kinda predictably lame writing to me.
Whole scene doesn't ring true to me. Unlike the scene with Robin Williams where Damon (Matt Damon!) makes the wrong remark about Willliams's wife, and Williams takes a stand from his strong-but-passive demeanor, in which everything deflected off of him. Not quite as predictable (as was Williams's demeanor - not really predictable).
"Fortunately, I'm adhering to a pretty strict, uh, drug, uh, regimen to keep my mind, you know, uh, limber." - The Dude