You have to realize that when people make mistakes, there's two ways to look at it. Your job as a co is not to crank out people who are a cooky cutter person. Your job is actually to cultivate someone's natural skills and help them figure out a place where they can perform for the betterment of the organization. If you don't fire people, first of al, understand this: The entire rest of your team knows who shouldn't be fired. And if you think you're weak about firing people, what do you guess? You're losing respect.