It's his problem
Once a Zen master was walking along with a student in a busy marketplace.
Out of nowhere a man running on the road runs into the Zen master.
The Zen master falls down. But he gets up dusts his clothes and moves on, unruffled.
The student is shocked by the master’s behavior.
“Master, why did you not react to the man’s wild push? Are you not bothered? Who he is and why he did this?” said the student.
“That’s his problem, not mine,” replied the master continuing the journey as if nothing had happened.
Note: Often the ego, our exaggerated sense of self importance, causes us to react to situations. And heap misery on oneself. To the man who is humble and egoless, it’s futile to react or worry about why someone said or did something. That’s best left to idle and ignorant minds. There are better things to do in life.