“When Voldemort was 16 he was becoming immortal, when his Harrys dad was 15 he could already do silent spells, when Snivellus was 16 he was inventing spells and creating new ways of making potions, when Draco bloody Malfoy is 16, not only can he do occulemency, but he made up a plan that lead to the death of one of the most powerful wizards in the world. Heck, even Peter was an animagus when he was what, 15, 16. What the hell is Harry doing?
Thats the crux of the matter, isn't it. All this time Harry hasn't tried to better himself, yet he has all these examples of wizards beginning to show greatness at the same age as he. Dumbledore can be added to the list above, remember the O.W.L. examiner said that she saw Dumbledore do things with a wand in his exam that she had never seen before? Harry seems unmotivated and unwilling to work, or even to try to gain anything - power, greatness, or just vengeance on his parent's murderer.”