A tap on the shoulder

A passenger in a taxi leaned over to ask the driver a question and
tapped him on the shoulder. 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,
and then the still shaking driver said, "I'm sorry, but you scared the
daylights out of me."
The frightened passenger apologized to the driver and said he
didn't realize a mere tap on the shoulder could frighten him so much.

The driver replied, "No, no, I'm sorry, it's entirely my fault. Today is my
first day driving a cab.
I've been driving a hearse for the last 25 years !."