I flew a trip with the "great day" dude a few months ago and found him completely genuine, affiable and optimistic. He told me a somewhat apocryphal story about flying a few days after 9-11. It was the first day back to flying and the ground controller (maybe Philly?) was absolutely raping the flights--yelling at folks, mean spirited and otherwise miserable. The GD guy calls USAir XXX taxi with C, GREAT DAY!" The controller shot back "WHAT'S SO GREAT ABOUT IT?"
The freq grew aboslutely silent. The dude replied "Well, my wife loves me, my kids are healthy, I still have a job, and I wasn't one of the 4,000 people killed a few days ago. So it's a great day..."
You could have heard a pin drop--no one said anything for 30 seconds. The ground controller finally came back on the freq and was actually crying. Apologizing to the crowd, he mellowed out a bit.
Sounds made up, I know, but I believe it...Words DO have an effect of folks, you know.