Not to  talk to a person who is worthy of talking to is to lose the person. And to speak to a person who is not worthy of conversation is to lose words. The wise man loses neither people nor words.  (Confucius)     

Не поговорить с человеком, который достоин разговора, - значит потерять человека. А говорить с человеком, который разговора не достоин, - значит терять слова. Мудрый не теряет ни людей, ни слова.  (Конфуций)   

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Never have men treated each other with such exasperation, never have they been so blinded as in our time, when they have come to imagine that they know everything. (Emile Zola)