Harry has a different reaction to being beaten by Vernon Dursley on submitting his report card, just before his 7th birthday. Revenge is on his mind. There will be bashing, especially of Albus Dumbledore. When you're the 'second-coming of Merlin', you get praised for everything. When things don't go well, you get blamed for everything.
Harry has just been killed by Lord Voldemort and is sitting in a very white and empty King's Cross Station. Dumbledore pops in for a chat. Harry decides to stay a while. Death pops in for a chat. Harry decides to go back to save Sirius on 6th June 1994. Of course, since it's Harry Potter, things go awry.
Harry plays it smarter on receiving his Hogwarts Invitation letter.