Kurt Vonnegut

"And now I want to tell you about my late Uncle Alex. He was my father’s kid brother, a childless graduate of Harvard who was an honest life insurance salesman in Indianapolis. He was well-read and wise. And his principal complaint about other human beings was that they so seldom noticed it when they were happy. So when we were drinking lemonade under an apple tree in the summer, say, and talking lazily about this and that, almost buzzing like honeybees, Uncle Alex would suddenly interrupt the agreeable blather to exclaim, 'If this isn’t nice, I don’t know what is.'

"So I do the same now, and so do my kids and grandkids. And I urge you to please notice when you are happy, and exclaim or murmur or think at some point, 'If this isn’t nice, I don’t know what is.'"