When a favorite character from a book or comic book gets adapted into a film, there is always going to be a lot of pressure on casting. Fans want to see their favorite characters come to life just as they imagine them, and that starts with casting the right actor. Of course, not everybody is always happy. Frequently new casting announcements are met with hate, even if they are eventually embraced.
Keanu Reeves as John Constantine was one such casting decision. When he was originally cast in "Constantine," fans had a real problem. To be sure, he looked almost nothing like the character as he was portrayed in the comics, so those looking for a traditional adaptation were out of luck. Frank Cappello, who wrote the screenplay for the first movie, recently appeared in a Reddit AMA where he discussed the hate he saw from fans online who were unhappy with Keanu’s casting.
