Actually, it was Lucius Malfoy who planned that diary scheme.

Voldemort’s stupid decision was trusting Lucius with said diary.

9:21 “he was such a bright, charming boy, we never thought he’d be the dark lord!”
Then, every single scene we see with young Tom, he’s acting like a creep and is openly disturbing to everyone he meets

The guy who desired immortality but failed to protect his lifelines until they were mostly all destroyed.

Emperor Palatine - I took over the galaxy
Sauron - I took over vast amounts of territory of Middle Earth
Voldemort - I almost took over a high school

The problem with Voldemort is his arrogance, hubris, delusions, and general stupidity aren't properly represented in the movies like they are in the books. Homie chose magical artifacts with elaborate holding locations because he was literally a drama queen that thought he was the chosen one. He could have imbued literal garbage and hid it in a landfill about to be sealed beneath the land, but he didn't because that would have wounded his titanic ego.

This dude kept losing to a literal CHILD, he’s the biggest villain too stupid to win imo.

Voldemort’s entire plan was reliant on no one trying to stop him

The Ministry of Magic deserves its own video

Imbue 6 grains of sand.  Sail to the middle of the Atlantic.  Drop the sand into the water.  Boom, immortality.

The Wizarding World should be part of "Civilizations Too Dumb to Exist"...

The most dangerous Dark Wizard of all time somehow can't conquer a high school.

The only thing magical about Hogwarts is how it hasn't been shut down for health and safety violations...

The dumbest thing about Voldemort was his goals. You are the the most powerful wizard in the world and can do anything you want and you choose to be a government beurecat?

Ah yes, the tale of the dark lord of magic who lost a fight to a baby and kept stacking Ls ever since.

This one is good because the reasoning isn't so much "bad writing" as it is the character's narcissism. He's actually so over confident that he really would make all these mistakes

I remember a HP fanfic explain away the plot hole with the Horcuxes by the fact that they need to have personal meaning to the maker and need to be hidden in places of deep personal meaning, otherwise the soul parts won't fuse to them.

Ah, yes, Tom "Noseless" Riddle...Probably the go-to case of villainous stupidity.
He doesn't die because he can't understand love, he dies because he can't understand how humans fight wars and only won the first time because his enemies know even less about how humans fight wars.

Wizard domination is a pipe dream from the start, their tactics haven't evolved since bronze age.

"mate serious you played yourself and are gonna die if you cast one more"
"SILENCE, BOY! I ALONE AM THE BESTEST EVAR! AVADA KEDAVRAAAAA-ACK"

My favorite thing about Voldemort leaving the diadem in the Room of Requirement--he thought he was the only person clever enough to find the room, despite the place being FILLED with junk that hundreds of other students had left there before him.

Slughorn be like: Yeah i'm gonna tell this radical teenager how to make a Mythical object that can make it inmortal and i'm gonna explain him what happens if you make many... i'm pretty sure nothing wrong will happen