One of the topics most often discussed in the Harry Potter fandom is why Voldemort - seemingly the most powerful Dark Wizard in the world - chose to use spellwork to kill Harry as a baby, rather than any other means. While it's arguably down to the fact that Voldemort entirely rejected his muggle roots, and would have been too arrogant to believe anything could go wrong, it ended up being a decision that would lead to his demise... and potentially, a key point in the argument that he was actually pretty incompetent.
Voldemort is not the only one of the series’ villains, even the most charismatic and interesting of them, who show, through their actions, just how incompetent they actually are. Ultimately, their inability to see things through to the end–whether because of ineptitude or because of their own overabundance of enthusiasm–shows how evil often ends up subverting its own successes.
Barty Crouch Jr.
David Tennant has been in many great roles, and he brings a frantic, almost bizarre energy to his characterization of Barty Crouch Jr. Crouch is arguably one of Voldemort’s most devout followers, but it can’t be said that he is always the most competent.
Though he successfully keeps the real Moody prisoner, he all too frequently lets his ionate devotion to Voldemort get the better of him, as when he reveals his identity to Harry by asking strange questions about the Dark Lord.
Professor Quirrell
Professor Quirrell, despite his trembling and shy demeanor, is in fact a very sinister villain, as he shows when he confronts Harry in the first novel and book. Though he has the competence to keep himself hidden from almost everyone (except for Snape, who immediately distrusts him), he also doesn’t have quite the competence he needs in order to bring Lord Voldemort back to life.
Like his master, he is not competent enough to realize that love is a powerful enough force to defeat even his own nefarious schemes.
Vernon Dursley
In the Dursley family, Vernon likes to think that he rules with an iron fist, particularly when it comes to Harry. It’s for this reason that, in the very first movie and book, he does everything in his power to try to keep Harry from attending Hogwarts.
Unfortunately for him (but fortunately for Harry), he proves to be as incompetent dueling against the forces of magic as his son will later be. When it comes right down to it, he is not nearly as competent, or as intelligent, as he believes himself to be.
Peter Pettigrew
Peter Pettigrew is, in his own way, one of the most evil Harry Potter characters. After all, this is the person who betrayed Lily and James Potter to their deaths. He is also remarkably cunning, able to hide himself in plain sight as the rat, Scabbers.
However, he also has his fair share of incompetent moments, particularly when he decides not to betray Harry’s presence. It is, unfortunately for him, this very act which seals his fate, as he is strangled to death by his own artificial hand.
Lucius Malfoy
At first glance, it might seem as if Lucius is actually one of the series’ more competent villains. He is, after all, one of its most compelling and sinisterly charismatic characters. However, it is also the case that his intelligence and his skills as a villain are often undercut by his own arrogance.
Like his son, he constantly believes that he knows better than anyone else. However, as his failure to procure the prophecy shows, he is his own worst enemy, and this leads him to fail the Dark Lord.
Draco Malfoy
Draco Malfoy is one of the most compelling characters, and he is one of the series’ most powerful Slytherins. While he likes to think of himself as being very intelligent–far more so than Crabbe and Goyle–the truth is that he is not particularly competent.
It is often the case that his innate sense of rightness subverts his desire to be a Death Eater. It’s why, for example, he cannot bring himself to kill Dumbledore, even though he knows that failing to do so will earn him Voldemort’s wrath.
Dudley Dursley
The Dursleys are some of the most unpleasant characters in the Harry Potter franchise, and they go out of their way to make the young man’s life an absolute misery. However, for all that they succeed in this effort, they are also notoriously incompetent.
This is very true of Dudley in particular, who is very often so concerned with the fulfillment of his immediate needs that he neglects almost everything else. And, as he shows with his encounter with the Dementors, he is utterly defenseless against anything magical.
Gilderoy Lockhart
Gilderoy Lockhart is notable for being one of the series’ most prominent Hufflepuffs. However, though he is very famous, it turns out that everything he has done is based on a lie and his skill with brainwashing other, more talented wizards and witches.
When it comes right down to it, however, he is ultimately undone by not only his own incompetence but also by his desire to have his precious reputation kept intact. It’s easy to see how, had he done a few things differently, he could have become a truly great wizard rather than a laughingstock.
Crabbe
Crabbe is one of the many secondary characters who inhabit the Harry Potter world, and he is best known for being one of Draco’s flunkies. Though he is a menacing person with a great deal of physical strength and menace, the truth is that he is not particularly competent at much of anything.
In fact, he relies a great deal on Draco to tell him what to do. In this respect, he has a great deal in common with his father, who is similarly subservient to Lucius.
Cornelius Fudge
The Ministry of Magic is one of the most important organizations in the Harry Potter universe. Unfortunately, it is not always led by the most competent people, as can be seen by Cornelius Fudge.
He is certainly this series’ most incompetent villain because, in trying to keep everyone from finding out about Voldemort’s return, he hamstrings his own organization’s ability to mount an effective resistance. He is the type of person who is always more concerned about perception than reality, and very nearly ruins everything because of his incompetence.
