10 Worst Decisions Harry Potter Ever Made
5. Not Taking Occlumency Seriously
In Order of the Phoenix, Harry's mind was being probed by Voldemort through their shared connection. Under the advice of Dumbledore, Harry was told to take Occlumency lessons from Professor Snape, the skill of blocking off one's mind in order to prevent anyone entering it.
However, through Snape's strict methods, Harry rejected the lessons and resisted the teachings. This was a decision based off his childish loathing of Snape and his stubbornness in learning.
His rejection of Occlumency meant that Voldemort could still manipulate his mind and bait him into a trap, which led to Sirius Black's death. Harry's choice was a misguided and spiteful act that caused problems to everyone around him and that resulted in his godfather's murder.