When nothing else works, try this
From Dale Carnegie's How to Win Friends and Influence People, an anecdote about how Charles Schwab wordlessly motivated the workers in one of his steel mills.
Charles Schwab had a mill manager whose people weren't producing their quota of work.
"How is it," Schwab asked him, "that a manager as capable as you can't make this mill turn out what it should?"
"I don't know," the manager replied. "I've coaxed the men, I've pushed them, I've sworn and cussed, I've threatened them with damnation and being fired. But nothing works. They just won't produce."
This conversation took place at the end of the day, just before the night shift came on. Schwab asked the manager for a piece of chalk, then, turning to the nearest man, asked: "How many heats did your shift make today?"
Without another word, Schwab chalked a big figure six on the floor, and walked away.
When the night shift came in, they saw the "6" and asked what it meant.
"The big boss was in here today," the day people said.
"He asked us how many heats we made, and we told him six. He chalked it down on the floor."
The next morning Schwab walked through the mill again. The night shift had rubbed out "6" and replaced it with a big "7."
When the day shift reported for work the next morning, they saw a big "7" chalked on the floor. So the night shift thought they were better than the day shift did they? Well, they would show the night shift a thing or two. The crew pitched in with enthusiasm, and when they quit that night, they left behind them an enormous, swaggering "10." Things were stepping up.
Shortly this mill, which had been lagging way behind in production, was turning out more work than any other mill in the plant.
Let Charles Schwab say it in his own words: "The way to get things done," says Schwab, "is to stimulate competition. I do not mean in a sordid, money-getting way, but in the desire to excel."
The desire to excel! The challenge! Throwing down the gauntlet! An infallible way of appealing to people of spirit.