"It is impossible to suffer without making someone pay for it; every complaint already contains revenge"

This quote by Friedrich Nietzsche recommends that when someone suffers or experiences pain or hardship, they often feel the need to make another person spend for it. A problem, or expressing one's dissatisfaction, is currently an act of vengeance in itself. In other words, according to Nietzsche, people tend to look for revenge when they experience difficulty or suffering.