Revenge is a dish best served cold

From my understanding to this phrase that revenge that you should wait for a while while planning with a cool head and let enough time pass so that the person who wronged you forgets that you ever existed. And when your revenge come the person will be the one to be the first experienced your wrath as shocking and undeserved.
I never see a revenge with my own eyes that is ideally register as wildly and unjust cruelty, but because this is the world, full of unjust people, unfair to live for most of them, because of some heinous crimes, people are able to planned revenge for the unjustice system all throughout the world, peopling killing each other out of revenge and some of those are very terrifying. I could remember the movie from The Godfather trilogy that is all about crimes, a family of mafia, with their illegal businesses of illegal drugs and more.And because they are very influencial people that time, they had many enemies and the story is full of self-served revenge of cruelty and unstatisfying act of madness of killing.
There should be no rush to serve revenge, a year or 2 is enough to formulate and execute the plan to make it better, or delay if you need more time to plan and you will savor revenge more if you wait for itand i guess the one who wronged you would never suspected you and would think that its a revenge long overdue.
It is only an understandable opinion and there is no way or another that i am giving this as a tip or a way in doing such kind of revenge. I am not a killer, and i do not have an enemy.