Surely you've heard the joke. You tell Siri, "Call me an ambulance" and Siri responds, "From now on, I'll call you, 'An Ambulance', Okay?" As Leanna Lofte points out in a great writeup over at the iPhone Blog, that this joke can actually be of practical use.
You can create a more friendly identity for yourself by telling Siri to call you by your nickname, or simply indulge your monomaniacal streak by instructing her to call you "Master" or "Emperor" or similar.
Siri does this by checking out two fields in your primary Contacts entry. The Nickname field takes priority. When you say "Call me 'Master,'" Siri updates your nickname field directly. Keep