Dumbledore Had a Sneaky Purpose When Selecting Harry's Teachers, Fan Theory Claims
Being the teacher of Defense Against Dark Arts is no easy job: after Lord Voldemort cursed this position many years ago, not a single person managed to maintain it for more than a year.
Most of the teachers went out in a painful way, too, so no wonder the Headmaster had so much trouble finding someone to take the job.
The bad reputation of this position resulted in some very questionable people becoming teachers of Defense Against Dark Arts.
A literal Voldemort's vessel, a narcissistic criminal, a werewolf, a Death Eater, a sadist from the Ministry, and then two more Death Eaters.
It's a wonder so many students survived while having all these shady folks around, let alone managed to pass their exams.
But apart from the difficulty of finding a person for the job, Albus Dumbledore might have had another reason to hire these exact people.
As Reddit user myster__synester claims in their fan theory, each of the DADA teachers was specifically selected by the Headmaster to show Harry what could become of him.
Quirinus Quirrell was a weak man beholden by Lord Voldemort. He showed Harry how low can a weak person sink, and what serving the wrong master does to a man. He may be one of the reasons Harry valued his independence so much.
Gilderoy Lockhart was an absolute narcissist and an attention seeker. He was an example of what happens when you let fame get to your head, and after meeting Lockhart, Harry detested it more than ever before.
Remus Lupin was shunned and ostracized for what he was, but he managed to pull through thanks to his friends. He showed Harry how to remain a good person even in tough times, and how crucial friends are.
Alastor Moody was an extremely paranoid cynic always looking over his shoulder. By his example, Harry understood that if you're always searching for enemies, you can lose yourself to your fear and paranoia.
Dolores Umbridge was a power-drunk Ministry puppet, a mouthpiece for bureaucracy. She ensured Harry hates the Ministry and doesn't trust the authorities, and later he declines Scrimgeour's offer to not follow in her steps.
Severus Snape was a loyal and ultimately lonely man dedicated solely to his mission. He was to warn Harry of the risks of alienating himself from others and living in the past as it leads to a sad and miserable existence.
As we see in the later parts of the story, Harry actually follows the steps of Remus Lupin, the only Defense Against Dark Arts teacher he liked and felt a connection to.
All the others showed him what to avoid, and only Lupin taught him how to live through dark times and remain a good person.
So it seems that Dumbledore really did shape Harry's personality in more ways than you thought, but it only served the boy well and helped him become a better man.