You get what you give
If you're old enough to remember the New Radicals and their chart topping song in 1988 called 'You Get What You Give' Then you should be familiar with the concept, that what you put into something you will get out. Or put it another way, you reap what you sow. Despite these well-known expressions, some managers expect their staff to sow much more than they do themselves.
Give and take, don't just take, take, take, from your employees
As Leader, you should encourage your staff to go the 'extra mile', not only for the sake of completing the task at hand, but for the personal benefit of your employees. By emboldening your employees to stride out of their comfort zone, you also enhance their personal development; which is good for both them and your business.
As a manager, you will reap what you sow, be that either good or bad.
However, what is both unacceptable and unforgivable, is for a person in a management position to fail to unknowledge the extra effort their staff put into their role, either through lack of willingness to understand the contribution that their subordinate's make, or to dismiss the extra effort an employee makes, simply because you are too busy as a manager and couldn't be bothered to listen to your employees' concerns.
So remember, if you want your staff to go the extra mile, at least be prepared to give them a little more than an inch.