The real ingredients of Felix Felicis...Considering luck is really just a combination of probabilities, talents and intuition, examine how Harry acts after taking the stuff. Confident, determined, perceptive and charismatic. In light of the fact that the wizarding world and science are poles apart, they think it's magic. What is it really? A calibrated blend of Red Bull, alcohol and an opiate painkiller!
Slughorn chose the Drought of Living Death potion for the first day because...He knew the recipe in the book was substandard, and knew if anyone managed to pull the potion off properly instead of what you would get by following the instructions they would be deserving of the prize. He wanted a perfect potion - if the "best" in the class would have been merely passable, the prize would have not been handed out.
- This would imply that Hermione isn't so brilliant after all.
The recipe for the Drought of Living Death potion in Advanced Potion Making was dumbed down.So no students would make one that was actually dangerous. Not that there isn't plenty in the wizarding world at Hogwarts that could damage a person, but this particular author didn't want to contribute harm to anyone, or there are few remedies to this potion in its correctly-mixed form. After all, one would assume that Hermione - following the instructions as she does - would have passed this with flying colors.
- In the film, Slughorn even says Harry's is so perfect that "...a few drops would kill us all!"
The British Royal Family are all muggles.Harry is told "There are no wizarding princes".
In the film only: Dumbledore asked Harry about his relationship with Hermione because......at that time he was working on the Deluminator for Ron (he knew he'd be dying and was hard at work on his will) and wanted to make sure Harry starting a relationship with Hermione would be off the table - because if that happened Ron may not have been able to use the Deluminator to return.
Veelas have an opposite effect on females than they do on males.We never see a female character actively like Fleur or any other Veela for that matter. We know they draw men to them, and since almost every female who's around a Veela seems to actively dislike them, it's because the flip side to affecting one gender one way, is affecting the other in the opposite way.
The method of creating a Horcrux involves what Voldemort did to Bathilda in the next book, except transfiguring the body to "coat" the Horcrux. Ergo, you're not just using a person's murder to create a Horcrux- you're desecrating their body to protect it, even after death.
Harry hiding the book near the Diadem wasn't a Contrived Coincidence.Maybe horcruxes attract each other subconsciously.
The potion protecting the Horcrux contains....Essence of Dementor.. It would explain why when Dumbledore drinks it, it takes him back to his worst memories, including the death of Ariana.
Red Dwarf and Harry Potter take place in the same universe.The luck virus (from Quarantine, the episode with Mr. Flibble) is really just Felix Felicis in its most purified (and, for some reason, green) form.