What flips someone over from polite mode to friendly mode?

Having been indirectly responsible for the pit of depression Anfy's laptop has plunged itself into (that's a long story on its own, but suffice it to say that the laptop has decided it doesn't want to get up in the morning, or at any other time of the day either), I got the joyful task of taking it into the Apple centre to get it counselling.

It was all going quite smoothly with the sales assistant (let's call him Kevin because that's what his nametag said), checking off the contact details, what was in the laptop bag, etc, etc. He was pleasant, but just your standard non-memorable retail pleasant. But then, as I signed off on the manifest and hesitated over the date, he said, "Today's the 29th, all day" and I, talking out of the back of my brain (like I do) said, "Special offer, today only."

And all of a sudden Kevin's off in friendly mode, quipping about how today is the only day ever it's going to be the 29th of the 11th 2004 and what a unique day it is, and thenceforth for the rest of our dealings it's all chatter smile happy friendly joke quip. Like I flicked a switch.

Which was just as well because it's been a good six months since I used my savings card and I couldn't remember the pin. I needed three attempts. ("Don't worry," he said, "keep trying. I've got two more rolls of EFTPOS paper." and "They say never use your own birthday, so I always use someone else's." and "Well done, I knew you had it in you," when I finally got it right.)

Strange, that's all.