Trivia: When Neville receives a Remembrall from his grandmother, it glows red to inform him that he forgot something. Neville says that he can't remember what he forgot. If you look closely, Neville is one of very few students not wearing his robe. He most likely forgot to put his robe on.
Trivia: For anyone who hasn't read the book: The inscription on top of the Mirror of Erised says "erised stra ehru oyt ube cafru oyt on wohsi". If you read the inscription backwards it says "I show not your face but your heart's desire".
Trivia: The Hogwarts motto, 'Draco Dormiens Nunquam Titilandus', is Latin, and means 'Never tickle a sleeping dragon.'
Trivia: Richard Harris agreed to take the role as Albus Dumbledore only after his 11 year-old granddaughter threatened to never speak to him again.
Trivia: J. K. Rowling recently surpassed Agatha Christie as the world's most-published female author.
Trivia: Because the title for the US release was 'Harry Potter and the Sorcerer's Stone,' every time a character said 'Philosopher's' in a scene the crew would have to shoot that scene a second time and change the word to 'Sorcerer's' for the US release.
Trivia: Susan Bones, who was sorted into Hufflepuff, is shown prominently throughout the film, even in some of the Gryffindor classes. The reason she is used so much is that she is actually Chris Columbus's daughter, Eleanor.
Trivia: The name 'Voldemort' comes from the French 'vol de mort' which means 'flight of death'. This is perfectly descriptive of Voldemort, and is another interesting name from the brilliant mind of J. K. Rowling.
Trivia: J.K Rowling declined the offer to play Lily Potter.
Trivia: The original title of the book, and subsequently the movie, is 'Harry Potter and the Philosopher's Stone.' However, Scholastic, the American publisher of the book, decided to change it to 'Sorcerer' for the American publication.
Trivia: J.K. Rowling has stated in interviews that her favourite authors include Jane Austen. Was Filch's cat, Mrs Norris, named after the busybody in 'Mansfield Park'?
Trivia: Book author J.K. Rowling wanted former Monty Python member Terry Gilliam to direct. However, Warner Bros. chose Chris Columbus, who had experience directing child actors (most notably, Macauly Culkin in the "Home Alone" films). Interesingly, John Cleese, who was in Python with Gilliam, appears in the film as Nearly Headless Nick.
Trivia: David Thewlis, who later played Professor Lupin in "Harry Potter and the Prisoner of Azkaban," was considered for the role of Professor Quirrell. Ironically, Thewlis is friends with Ian Hart, who did play the role.
Trivia: The only major character left out of the film was Peeves the poltergeist - Rik Mayall was cast, and filmed all of his parts, but they were cut out due to the film's over-long running time.
Trivia: When Hermione shows Harry and Ron the Gryffindor Quidditch trophy with James Potter's name, to its left (viewer's right) the award for 'Special Services' is visible. Seen only on the full screen DVD are the last letters 'dle' at the top of the award - for Tom Riddle. (01:00:35)
Chosen answer: There are several reasons. First, the position is cursed, so there is little reason to give Snape the job when he will not last any longer than all the previous instructors. If Snape did become the DADA instructor, something could happen to him that could result in his being harmed, having to leave Hogwarts, or be otherwise incapacitated in some way; that would render him useless to Dumbledore as a double agent. Also, Dumbledore trusts Snape, but putting him in an environment where he is teaching about dark magic on a daily basis would be too tempting and emotionally compromising to someone who had been so easily seduced by the dark side. He could possibly relapse. It would be like having a recovering alcoholic work as a bartender. Of course, he does eventually become the DADA instructor, and lasted no longer than his predecessors.
In the movies it is never mentioned that DADA role was cursed by Voldemort.