A passenger in a taxi leaned over to ask the driver a question and gently tapped him on the shoulder to get his attention.
 
The driver screamed, lost  control of the cab, nearly hit a bus, drove up over the curb and stopped just inches from a large plate glass window.

For a few moments everything was silent in the cab. Then, the still shaking driver said, 'Are you OK? I'm so sorry, but you scared the daylights out of me.'
 
The badly shaken passenger apologized to the driver and said, 'I didn't realize that a mere tap on the shoulder would startle you so badly.'
 
The driver replied, 'No, no, I'm the one who is sorry, it's entirely my fault. Today is my very first day driving a cab. I've been driving a hearse for the past 25 years.