FIRST TIME EXPERIENCE

After walking for so long, the passenger patted the taxi driver on the shoulder to ask something. The reaction was unexpected. The taxi driver was so shocked that he accidentally stepped on the gas deeper and nearly hit another car. Finally he can master the wheel and stop his car on the roadside.
"Please do not ever do that again," said the taxi driver, pale and angry.
"I'm sorry, I do not mean to surprise, I do not think that touching shoulders can be so shocking to you."
"The problem is this is the first day I am a taxi driver and I am the first passenger."
"Oh so, how can you be so shocked?"
"Before I was a hearse driver."