Jim Sinegal, Co-Founder and Director, Costco Wholesale Corp.

"If you're a manager, teaching is 90 percent of your job. There's only one reason you hire someone, and that's because you can’t do everything yourself. If you're not prepared to teach, you just don't get it. And if you hire well, and if you teach well, those people wind up doing the job better than you would have done it anyway."