I found this facinating story about the OK and Cancel dialog on the original mac. The Folklore website is absolutly facinating and gives a good glimpse into what it's like to build an operating system.
Interestingly, Steve Capps who is mentioned in many of the stories later joined Microsoft where I had the pleasure to work with him on a number of projects including the early designs of Windows XP.
Storytelling is a interesting subtext to how software is built. If you have links to other stories of how software is built in the trenches please add your comments.