My mother always said that it was better to be a pessamist. The optomists just sit around thinking pure thoughts and quoting Norman Vincent Peale, while the pessamists will glare, grumble, and take care of the problem because it's not going to fix itself.
Me, I'm a contrarian.
Although I'm a bit dour and melancholiac by nature, I'm the one that states the other point of view when someone gripes about, say, the weather: "We need the rain.""If we don't have a cold spell in winter, we won't have an apple crop; that's why apples don't grow in Guatemala." Hey, it's February in northern Ohio, and I'm being paid to stay inside a nice warm, dry building."
"Have a nice day? You're telling Me to Have A Nice Day?! Stick it in your ear!"