12 Dumbest Decisions In Harry Potter Movies

7. Harry Not Committing To Occlumency

Harry killed Sirius Black. There's no getting around the fact. Yes, Bellatrix Lestrange might have cast the fatal curse but it was Harry's neglect of the two-way mirror and his refusal to take his occlumency lessons from Snape seriously that lined up the cross-hairs.

Instead of just doing as he was told by the unhelpfully vague Dumbledore and actually learning how to guard his mind from Voldemort, Harry acted like a spiteful brat. He couldn't put his personal feelings aside for the greater good or even listen to Hermione's desperate pleas to learn it properly for a few hours and in the end, he kept open a vulnerability that killed the closest thing to real, loving family he'd ever had.