Getting frustrated at a coworker's promotion is not unusual in the workplace. We're only human, and if we feel ever so slightly envious, that's understandable. However, allowing those jealous feelings to take over and cause a major interruption to everyone else's workflow is nothing more than an act of supreme selfishness, even if you were qualified for said promotion. This Karen took it too far when she didn't like the fact that her coworker, who managed the volunteer department at a small mun…