To know if someone can speak offensively or politely, don’t give him poem to recite; don’t give him a song to sing. Just engage him in an argument and you will know it for yourself who he is.
~ Israelmore Ayivor
Avoid the use of abusive words when communication is in session, you might scare away someone who is meant to become your mentor or your customer.
Talk to strangers politely... Every friend you have now was once a stranger, although not every stranger becomes a friend.
It is unpredictable for you to know which of the strangers you are about to meet that becomes your friend. Be polite to every stranger!