How many alters does it take to screw in a light bulb?

I thought this was REALLY cute. I got it from Reddit.com

How many alters does it take to screw in a light bulb?
*One to freak out about the darkness
*One to call the first one a baby
*One to tell the second one to shut up
*One to complain that the light makes her look fat
And at some point during all of this arguing, the light bulb gets changed, but nobody knows who did it.