This chapter reveals Harry's self-doubt to a greater degree than we have seen before. He always is frightened but brave when encountering new and trying situations, but in these moments, he doubts his wizarding knowledge and abilities, rather that doubting his own morality or motives. He simply assumes that he is a good person who has had certain fortunate and unfortunate happenings in his life, and here he worries late into the night that he was destined to be a Slytherin, and that he is responsible in some way for these tragedies at Hogewarts. He cannot easily dismiss these fears. He is certainly an unusual student, marked by a scar, the ability to speak Parseltongue, certain heroic victories in his first year, and also a strange voice speaking to him around the time of the killings. When strange things happen at Hogwarts, Harry is almost certainly involved. He has never been exceptionally pleased or traumatized by this extra attention, but rather he just takes is as part of the hand he has been dealt. Here, the fact that he is a public and closely watched figure works against him, making him a more potent suspect, a more likely threat to Voldemort, and also giving his famous childhood trauma a fresh, gossipy spin.