Engaging in a petty back-and-forth with your coworker is, more often than not, a recipe for disaster. However, sometimes you have no choice but to defend yourself. Here, we have a 29-year-old bartender who often was put on the closing shifts at the small but popular bar where she worked. One morning, her coworker who was on the subsequent opening shift tried to get her in trouble with their manager for a mistake she had not made the night before. So, the Redditor decided that the best way to ge…