Advice Polonius gave his son Laertes before Laertes left for France.
Never say what you’re thinking nor put hasty thoughts to action. Be friendly but don’t cheapen yourself. Those friends who’ve proved themselves by experience, grasp them to your soul with bands of steel. But don’t offer the hand of friendship to every new-made, unproven, back slapping, acquaintance. Beware of starting a quarrel, but once involved, see that your opponent gets more than he bargained for. Hear all, but say little. Take everyone’s opinion but keep your own judgment to yourself. Dress well as you can afford but don’t go to extremes of fashion– good quality rather than loudness– because you can easily tell one by their style of clothes. Be neither a borrower nor a lender. A loan often loses both the money and the friend, and borrowing makes one spendthrift. Be consistent: as night follow day, surely you cannot deceive anyone.
—Polonius, from Hamlet