The one thing you do know about Friday the 13th is that you had a restless night's sleep the first time you saw it. We're also going to guess that you were probably too young to really be watching it...
But other than that, we're guessing your knowledge might be rather basic. We've decided to illuminate some of the film's finer points and put together 15 incredible facts that you might not really be aware of...
(Images: Rex Features, All Star)
Harry Crosby, who plays Bill, is actually the fifth son of Bing Crosby.
The filmmakers were really keen to get Sally Field for the role of Alice but she turned it down and they went with Adrienne King instead.
Despite his name now being the stuff of horror movie legend, Jason Voorhees was originally called Josh. The script had him down as Josh Voorhees until writer Victor Miller thought it sounded too nice and instead used the name of a school bully. Josh X, anyone?
The film was originally supposed to be called Long Night At Camp Blood
There was a film released in 1979 called Friday the 13th: The Orphan and a settlement had to be negotiated in order for Friday the 13th to then be used.
The ending was directly influenced by Carrie and was actually suggested by makeup designer Tom Savini, who was brutally honest about this. "The whole reason for the cliffhanger at the end was I had just seen Carrie, so we thought that we need a 'chair jumper' like that, and I said, 'let's bring in Jason'".
The story of Mrs Voorhees was given more development in a novelisation in 1987. She had tried to move on after Jason's death but her psychosis got the better of her and when the camp was reopened, she was worried that it would happen again to someone else. There was also a prequel called Friday the 13th: Pamela's Tale, which was a two-issue comic.
Director Sean S Cunningham was originally going to play the role of Officer Dorf but actor Ron Millkie, who had worked with him years earlier, called him as he'd heard about the film. Because of this, Millkie then took on the part instead.
The original scripted ending had "two bureaucrats" stumbling upon all of the dead characters from the film hanging from a tree and then Alice, with Mrs Voorhees' severed head in her lap.
Despite the film's commercial success and iconic status, it was nominated for two Razzies: Worst Picture and Worst Supporting Actress for Betsy Palmer, aka Mrs Voorhees.
The actual location used in the film was a Boy Scout camp called Camp No-Be-Bo-Sco in New Jersey. It still stands and is used as a summer camp.
Director Sean S. Cunningham originally wanted to cast his son Noel in the role of Jason but, understandably, his wife was against it.
The budget was a mere $550,000 but it made $59 million in the US alone. With inflation, that would be over $117 million now.
Even though Betsy Palmer (Mrs Voorhees) is the top-billed cast member, she's actually only on screen for 13 minutes. Throughout most of the film, a male stunt double is used.
The role of Mrs Voorhees was originally set to be played by Estelle Parsons, best known for her Oscar-winning role in Bonnie & Clyde.