One wise man once said: "Why would you want to waste your time and energy to do revenge, if karma is already working and doing that?" ~Sadhguru.
Many people heard of karma, but they only use it when they have witnessed something happening to others who "deserve" it or they looking at it as a last resort in desperation. Karma is a word from India foreigners will probably never fully understand, because it is linked to the culture, history, religion, mysticism and is embedding a combination of many meanings. You can understand Karma as energy mechanics. Simply put, what goes out - must come in.
One of the universal laws is about energy and because you consist of energy, you have a certain resonance and by saying "you" I mean your mind. Based on your thoughts you create, your energy is changing, therefore your resonance frequency is changing. That is already measurable today. What this have to do with Karma and revenge you ask? Imagine you have an energy tank and that tank is filled with negative and positive energy. If you spend and release positive energy out, the empty space needs to be replaced with a new energy of the same kind, in this case positive. What goes out, must come in. If you release negative energy, the negative energy needs to come back. This is not an instantaneous process, but it will manifest.
And so if we come back to the revenge piece then there is no point seeking revenge if somebody has hurt your ego a bit or caused harm. The energy mechanics are already in work and the negative energy spent is already attracting new negative energy to come in. The Karma is at work already, why would you waste your own energy and time? Besides, the moment you spent your energy in a negative way, it will come back to you. It's like 'killing for peace' or 'shouting for quiet'. The desired result will never be reached. It's impossible...