My answer to Jaffe’s question would be: ” None ’cause chances are your client still lives in the Dark Ages”.
Now I really like the “Maybe we should listen to the light bulb first and find out if it really wants to be changed….” though for the sake of the argument we could argue that when the light bulb has to be changed its either for relevant reasons that might transcend its will (like ecological arguments) or because the light bulb is dead. In both cases discussion is not an option 
Definitely good material for an other best seller in the ‘Shaggy Blog Stories’ collection 
If you want have fun with it, take a look at my 2006 year-end post post with the full horoscope of characters, which one are you?
How Many Bloggers Does it Take to Change a Lightbulb?
OK OK Valeria, I could not agree more with your profile description. I am a true Leo … and a Leo does not change light bulbs. ‘At most, a Leo will hold the light bulb while the world revolves around them.’… so much for a bit of introspective psychology