I love the book Whale Done, by Ken Blanchard. If you haven't read it, it is a quick read and I highly recommend it. And his other books, The One Minute Manager, Raving Fans, Gung Ho. His books are simple ideas that many of us learned early in life, but sort of forgot along the way.
So there goes any form of criticism right out the window. Along with it goes most sarcasm. Darn, because I like sarcasm. I'm really pretty darned good at sarcasm. But it doesn't get you anything but a momentary sense of righteous indignation. It doesn't teach anything. And it doesn't encourage the behavior you like to see in the people around you.