The theme for chapter 5 is being a stranger. I'm going to deviate. This is the chapter where Hagrid says the famous line of "There's not a single witch or wizard who went bad who wasn't in Slytherin. You-Know-Who was one" As a proud Slytherin this makes my blood boil a little bit. Not all of us are bad. As a matter of fact with this post I have included 3 wizards who are bad but are not from Slytherin. Peter Pettigrew was a Gryffindor, Professor Quirrell was a Ravenclaw, and Barty Crouch Jr. is theorized to be a Ravenclaw. (I tweeted JK Rowling about this for an official answer) To bring this post back to the theme, Harry definitely feels like a stranger in this brand new world that has opened up to him. Everyone knows him but to him this is all so new.