What not to wear.

Former Harvard University president Larry Summers gave the audience at Fortune's Brainstorm Tech conference the real back story on a familiar scene from The Social Network. In Aaron Sorkin's version of events, Mr. Summers couldn't be bothered with Cameron and Tyler Winklevoss' attempt to halt Mark Zuckerberg's world domination with Harvard's code of conduct. But what Mr. Summers was really thinking may have been worse. "Rarely, have I encountered such swagger, and I tried to respond in kind," he told the crowd, adding:

"One of the things you learn as a college president is that if an undergraduate is wearing a tie and jacket on Thursday afternoon at three o'clock, there are two possibilities. One is that they're looking for a job and have an interview; the other is that they are an asshole. This was the latter case."

Another reason to keep the start-up dress code "business shabby."