The Villain Sucks

Even evil can be bad at what it's supposed to do.

This might be because the Villain is a Joke Villain, the Jerkass, or some other role that flounders in the villainy department. Their henchmen might get tired of their suck-ass failure-at-everything attitude and quit the job. The Hero might even call the Villain pathetic. The worst thing that could happen to the Villain is if the people they're suppose to intimidate laugh at them and don't feel threatened by them any longer.