Whether it's a cheating spouse, a friend who takes you for granted, or a coworker who stabs you in the back whenever you're not present, no one should make excuses for another person's unsavory behavior. If the person is making a genuine effort to clean up their act, that's one thing. But if they pledge they're going to change, and yet you catch them pulling the same stunts over and over again, they're making a mockery of your compassion. At that point, you have to decide whether to continue giving them the benefit of the doubt, or calling it quits once and for all. It isn't as easy to walk when you're dealing with a coworker and you wish to keep your job. In that case, you may consider asking for a transfer or moving to a cubicle further away from the individual. You might also think twice about ending the friendship if you each have mutual friends. You may worry that he or she will talk smack to the others about you (if they haven't alr...