"We begin well, sir," the fat man purred … "I distrust a man that says when. If he's got to be careful not to drink too much it's because he's not to be trusted when he does. … Well, sir, here's to plain speaking and clear understanding. … You're a close-mouthed man?"
Spade shook his head. "I like to talk."
"Better and better!" the fat man exclaimed. "I distrust a close-mouthed man. He generally picks the wrong time to talk and says the wrong things. Talking's something you can't do judiciously unless you keep in practice."

Chap. 11, "The Fat Man" - The Maltese Falcon (1930)