Are grumpy workers the best workers?

"Recent research shows it could be the grumpy workers who are actually a company's most creative problem-solvers, said Jing Zhou, associate professor of management at the Jesse H. Jones Graduate School of Management at Rice University.

It's the happy, cheerful folks who tend to think things are going well and that there are no problems to be solved, she said. They're less likely to be pondering potential pitfalls and often don't see problems until there is a crisis".

The exception of course being government/city employees.