Imagine what it would be like if I were appointed by the courts to be an avenging angel and took that drunk driver out behind my house and literally beat him to death. You might get a brief sense of satisfaction from it, but it would not bring your son back, and you would not be genuinely happy. All you'd have is a handful of justice, and that is not happiness. It's not even close. You'd still be alone, and you'd still be angry.
Anger is a poison.
It's a cancer that's eating you up and destroying your happiness. If I killed that drunk driver, you might feel better for a moment, but it wouldn't last. Angry people use blaming and justice like drug addicts use their favorite drug. The effect always wears off, and they always need more. Justice and anger will never make you happy.