Define And The Bus Driver Stood Up And Started Clapping Meaning

And The Bus Driver Stood Up And Started Clapping
The phrase that originally came from poland. It is supposed to signalise disbelief in someone's story that supposedly happened in real life.

-So yesterday, I was with my niece at the shopping mall. There was a woman screaming at the cashier. Then, my niece walked to her and gently asked her to calm down!
-Yeah, and the bus driver stood up and started clapping.
By Estell