If you and I want to stir up a resentment tomorrow that may rankle across the decades and endure until death, just let us indulge in a little stinging criticism - no matter how certain we are that it is justified.
Dale CarnegieThe value of a smile... It costs nothing, but creates much. It enriches those who receive, without impoverishing those who give. It happens in a flash and the memory of it sometimes lasts forever. None are so rich they can get along without it, and none so poor but are richer for its benefits. It creates happiness in the home, fosters good will in a business, and is the countersign of friends.
Dale Carnegie