In the final Harry Potter book, Harry Potter borrows Hermione's Time Twister and goes back in time to remind me to post the next item on the list of "Final Harry Potter Book" items.
In the final Harry Potter book, Harry Potter finds Snape and kills him, only to find that Dumbledore was plotting the destruction of all of Hogwarts, and killing Snape has allowed Dumbledore's plans to go forward, leaving Harry to stop them, which he does, only to find out that Hogwarts is really a big bomb which will destroy the whole world. Way to go, Harry.
In the final Harry Potter book, Harry Potter finally manages to reach Shikai with his wand (turning it into a giant staff) and then, with Professor McGonagall's help, achieves Bankai in three days.
In the final Harry Potter book, Harry Potter watches helplessly as Voldemort kills Hermione, summons a giant Meteor to destroy the earth, only to be saved at the last minute by Hermione's ghost (or something) and watches as bright green lights destroy the meteor and most of Midgard. I mean, London.
In the final Harry Potter book, Harry Potter gets his broom up to 88 MPH and, after almost preventing his parents from meeting, prevents Voldemort from ever learning about Horcruxes.
In the final Harry Potter book, Harry Potter discovers a secret room underneath Hogwarts that allows him to cause the castle to fly, which he uses to chase down Voldemort's flying garden.