What are the dangers of seeking revenge?

Well, for one, you might get hurt, caught, or even killed in the process. Two, it becomes an ongoing battle between you and your rival. For example, many plots in stories on revenge are how their loved one were killed by someone and they seek that person to get their revenge from the loss they have experienced. But, if you think about it, its not going to bring back the person that was killed, only create more commotion and makes the situation messier.