Related:

• Never frighten a little man. He'll kill you. -- Lazarus Long, from Robert A.
  Heinlein's "Time Enough For Love...
• Never appeal to a man's "better nature." He may not have one.
  Invoking his self-interest gives you more leverage....
• Never frighten a small man -- he'll kill you.
• Courage is the complement of fear. A man who is fearless cannot be courageous.
  (He is also a fool.) -- Lazarus Long by Robert A Heinlei...
• Never underestimate the power of human stupidity. -- Lazarus Long by Robert A Heinlei
• Your enemy is never a villain in his own eyes. Keep this in mind
  it may offer a way to make him your friend. If not, you can kill him without hate - and quickly....
• Little girls, like butterflies, need no excuse. -- Lazarus Long, from Robert A.
  Heinlein's "Time Enough For Love...
• One man's theology is another man's belly laugh. -- Lazarus Long by Robert A Heinlei
• You live and learn. Or you don't live long. -- Lazarus Long by Robert A Heinlei