Prophecy
A prophecy doesn´t give you the right to choose, you´re just a path, a way for the destiny be fulfilled. Harry Potter knew that most than everyone. Treated as a Hero, Savior, the one that killed the Dark Lord and save the world. They never bothered asking if he was ok with that, no one cared anyway, as long as he managed to fulfill his role in the destiny game. Harry hated having his path ready for him to follow, it´s like everything of bad that had happened in his life was necessary, his parents death, his abuse at the hands of his uncle, having to beat Voldemort each single time, losing friends, family, people he cared, everything lead to the path of prophecy, and you can´t deny what´s already written.
Harry sometimes wonder if Voldemort used to think the same way as him, he was forced to try to kill the boy until he failed, but probably not, Voldemort at least had the chance to choose between him and Neville, the only choice that was given to him was die or defeat Voldemort, not exactly the fairest of choices. Unwillingly, Harry stood up and decided return to the castle, he had told everyone that he needed time alone after finally defeating Voldemort, truth be told, Harry still didn´t knew if the fulfillment of the prophecy gave him the right to finally live his life, perhaps he was only not needed anymore.
Prophecies are not forbidden, but Harry think they should be, really should be.