The iPhone could play a section of a song or a video, but it couldn’t play an entire clip reliably without crashing. It worked fine if you sent an e-mail and then surfed the Web. If you did those things in reverse, however, it might not. Hours of trial and error had helped the iPhone team develop what engineers called “the golden path,” a specific set of tasks, performed in a specific way and order, that made the phone look as if it worked.
So it turns out that the iPhone barely worked on the day it was introduced. Steve Jobs went as far as requiring his team to develop special hardware that would allow the device’s screen to be mirrored in live time on the screen. He had to perform certain actions in a certain order to keep the phone from crashing. Here’s the story of the employee who’s fault it would have been if the demo fell apart. Fascinating.