Because practice makes a man perfect. The Steve Jobs example.

Steve Jobs applied the same strict rules to himself, of course. He spent the two days preceding the keynotes rehearsing. "On the first day he worked on the segments he felt needed the most attention.

Steve Jobs keynotes were the most important and efficient means of communication for Apple. After all, this is how most of the world would ever see Apple — and Jobs, for that matter. They were used not only to attract the media's attention to new products, or to boost the faith of Apple fans worldwide, but even as an internal tool of communication. Indeed, the secrecy of the company made it so that most employees heard of their company's strategy and new products at keynote unveilings, while watching them in closed circuit TVs on campus.

After watching Jobs unveil the iPhone in 2007, Steve's old friend Alan Kay qualified the show, often considered Steve's best, with the words: "Steve understands desire."

The product managers and engineering managers for each new product were in the room, waiting for their turn. This group also formed Steve's impromptu test audience: he would often ask for their feedback". At this time he could still change the order of the presentation's mini-segments, and rearrange them to have the most impact. Then "on the day before showtime, things get much more structured, with at least one and sometimes two complete dress rehearsals. Any non-Apple presenters in the keynote take part on the second day (although they cannot be in the room while the secret parts [the product introductions] are being rehearsed.)

Finally came the time for the actual keynote. This was a hugely stressful moment for most people involved — including high-profile CEOs who were not all used to such large audiences and spotlight from the media. (Fox Entertainment CEO Jim Gianopulos told Jobs about his stage anxiety, to which he replied, "It's easy, you just imagine you have a few friends sitting around your living room and you're telling them what's new"). For Steve, it always came off as a brilliant and flawless performance that got everyone listening absolutely captivated. Although they were rare, he did have some embarrassing moments on stage, but he never lost his cool, and often even managed to joke about it: everyone remembers the clicker that stopped working at Macworld 2007, which made Steve contortion to distract the audience.