Hey, if I get my wallet, and my keys, get in my car and drive to a hamburger shop, I have an expectation.
I expect them to have a burger.
If they were to say, "No, we don't have burgers", then in the course of the next three seconds, the follow emotions happen.
1. I wasted my time.
2. I'm hungry.
3. I have to go elsewhere.
So my response is to say, "Hey darnit." What do you MEAN you don't have the burger that:
a) I'm supposed to pay for

Your reason to exist is to sell me one
c) I'm ready for and want one
The potential customer has to then process the fact that
1. They're not at McDonalds asking for a Whopper
2. Looking for cameras
3. Candid camera suspicions
Equals:
a) Disbelief

Overreation
c) Surprise
And now you have a commercial that depicts confused and surprised people as "Angry" that they can't have a Whopper. Because the voice overdub tells you that.
It's genius, really.
/I still like the Wendy's commercials from the 80's
//
Wheeeerrresss the beef?!///speaking of Wendy's, doesn't that guy with the red wig look like Cameron from Ferris Bueller's Day off?