Much of Notes from the Underground has to do with thwarted attempts at revenge. The Underground Man argues that revenge is more difficult – impossible, actually – for an intelligent and conscious man than it is for a normal "man of action." The reason is this: men of consciousness can't justify their need for revenge. They understand that it cannot be explained in a rational way, so they are paralyzed with inaction. Revenge, then, is portrayed as an outlet for spite. Without an external outlet like revenge, the Underground Man suffers inner anguish for decades when the smallest of offenses are done to him.
Notes from the Underground argues that revenge is always trivial and destructive to both parties involved.
Notes from the Underground argues that revenge is a necessary outlet for spite. Without it, we would all suffer like the Underground Man.