Author J.K. Rowling loves engaging with people on Twitter, from trolls to fans in need of a signal boost, but every once in awhile she sets off an Internet firestorm. This one started with an innocent question about why her most famous protagonist, Harry Potter, would name his son after Severus Snape, the teacher who tormented him and (spoiler) killed his wise mentor, Dumbledore.

Rowling answered:

Sources: J.K. Rowling