One fifth of workers hope to change career, with the desire for a better work life balance proving the main motivator, Mr Wallace said.

Another aide is quoted as saying that a desire to stop Romney was one of Perry's main motivators in running.

Religion and not nationality was the main motivator for confiscating land from the native Gaelic nobles.

Top profit has never been his main motivator.

"But your costs tend to be stable when you own, and that's a main motivator to home ownership."

Looking ahead, Mr. Rome says he is preparing for a time when fear of flying is no longer the main motivator for his customers.

The main motivator, however, seems to be the incentives.

Moral considerations aside, if those are your main motivators teaching is a really poor use of your skill set.

"It's customer-friendly, fun and engaging - that's the main motivator," he said.