Continuity mistake: When Harry is viewing Snape's memories, he witnesses a scene on Platform 9 3/4 between his mother and aunt Pentunia, in which Petunia tugs her hand out of Lily's grasp. Her hand is then back in Lily's and she tugs it out again.
Continuity mistake: When Harry talks to Griphook about breaking into Gringotts, Griphook has the Sword of Gryffindor in his hands. When Harry stands up to leave a few moment later, the sword is now beside Griphook's bed.
Answer: Rowling said she was going to wish him luck and acknowledge that her hatred of magic was based on jealousy.
Greg Dwyer