If a startling truth comes out of a "child's mouth," even the dumbest person can see through it. The great boss listens democratically. Don't disregard advice or information from someone who is false, stupid or deceitful. Don't ignore the words of talkative, fake or stupid people. Any word in there can reveal a clue, a truth, an answer or an idea. A great boss is someone who only cares about the quality of his opinion without knowing where it comes from.
Police investigators take clues and information from criminals and petty thieves. The police don't care that the clue was taken from good-for-nothing people. Most government intelligence-gathering agencies hire or bribe hired killers and thugs in exchange for vital information about infidels around the world. Excellent people are never picky about getting useful information from useless people.
Don't take advice given in a disgusting, crude, or insolent way lightly. Don't ignore irritable, loud, or sarcastic advice just because the words make your ears feel uncomfortable.