It has nothing to do with big bad sad America, or with Sid needing an attitude adjustment; it's run-of-the-mill social psychology. Everything beautiful is good, everything good is beautiful. Incidentally, that's why Sid isn't played by someone who's actually ugly or dorky or whatever negative appearance he's supposed to have - no one wants to watch regular-looking people do regular things. If that were what people wanted, they'd go interact with regular people rather than put the TV (or, now, computer). A real-life Sid WOULD go crazy going back and forth in appearance but remaining the same person, seeing firsthand the assumptions that are made based on someone's physical attractiveness. That's why the drink-spilling scene was so pivotal (also, I'm still LOL'ing at that guy saying, "This is a $32 shirt!").