A married couple were celebrating their golden wedding anniversary. Their three sons, all extremely successful and wealthy, agreed to a Sunday lunch to mark the occasion, but as usual they were all late and came up with a variety of excuses. The first son turned up fifteen minutes late. "Happy anniversary," he said. "Sorry I'm a bit late. I had a flat tyre this morning and as a result I'm afraid I haven't had time to get you a present." "Not to worry," said the father. "The important thing is th…