Three Sentences Spoiled A Banquet

A
rich man invited four friends to a banquet to celebrate his birthday. It was
already noon-time, but only Zhang, Wang and Li had come; his friend Zhao did not
appear, even though they waited a long time.
The rich man said anxiously, "Why isn't the one who should have come
here?"
His friend Zhang, an impetuous person, was very much upset at his words and said
to the rich man, "If the one who should have come isn't present, then I am
the one who should not have come. All right, good-bye." And with this, he
went away in a huff.
The rich man then said, even more anxiously, "The one who should not have
left has left."
These words aroused Wang's suspicion, so he said, "You said the one who
should not have left has left. Does that imply that I am the one who should have
left? All right, I have to say good-bye, too."
The remaining friend, Li, advised the rich man goodheartedly, "You should
learn what to say and what not to say; otherwise, you will annoy your guests and
send them away without your wishing it."
The rich man, hearing this, said, "Those two are too suspicious and
misunderstood my words. I didn't mean them."
Now it was Li's turn to flare up. "So it is I who should not have come; it
is also I who should have left." And with this, away he went.