Quotes from Dave Young

Also, remember that this is about the employee's performance and not his or her personality. You want your employees to be happy at work, but you don't want them to be happy if their work is not up to your standards.

The first thing to remember is that it's not about you, it's about them. If an employee can't do the job, then they have to go. The last thing you want is employees who are holding your business back or who are demoralizing their coworkers. Your credibility depends on getting rid of such people as soon as possible.

The key to really learning how to deal with difficult people is to understand that it is OK to not understand why they are the way they are.