In their bestselling book, Freakonomics, Steven D. Levitt and Stephen J. Dubner wrote, "An incentive is a bullet, a lever, a key: an often tiny object with astonishing power to change a situation."
It is true isn't it? Whenever there is a change in anything, there is an incentive for that change. You wouldn't change your job, your car or your wife/husband if there wasn't an incentive for doing that. Incentives comes in many forms, money and sex being the obvious.
MLM companies are raking in billions per year using money, freedom and a life of leisure as incentives. Politicians use incentives to get your votes. Religion works on incentives. Be good and you will be strolling in the gardens of paradise. Be a sinner and you are roasted meat.
In short, incentives rules our world (Mr. Bush might not agree). If you have proper incentives for the things you want others to do for you, you will always get what you want.