Demosthenes

Our regulatory bodies strive to create honest dealings, fair trades, and a situation in which no one has an advantage over anyone else. But human beings aren't honest. And all trades are made because one person thinks he's getting the better of the other, and the other person thinks the same.

I would absolutely recommend against excessive positivity and optimism. Any positive emotion that you're infusing into a workplace needs to be grounded in reality. If it's not realistic, sincere, meaningful, and individualized, it won't do much good.