Why eye contact between two strangers sometimes can lead to conflict?

Why eye contact between two strangers sometimes can lead to conflict?What are the causes?
Let see the example as follows:
Mr. A stares at Mr. B in the corridor, both are strangers to each others. Mr. B stares back and say:" Wei, why you stare at me?"
Mr. A say:" I'm not starring you, I see the tree besides you. Why? you not happy, isn't it? want to fight?"
Mr. B:" ---- you, you think I scare of you, come over here."
Then two person start fighting, attacking each others.
You see, a simple act can lead to tragedy sometimes.
Do you know why eye contact between two strangers can lead to conflict?
The conversation has shown:
They both like to win but in wrong path. They are too easily agitated by sights and words.
It is good to stay cool and not easily agitated by sights and words. It ready need " training " for them.
I want to say more but my eyes start to close, see you few days later.