Laughter during a horror movie is frequently taken as a bad sign, but for the directors of The Blair Witch Project, it was a guarantee that things were going well.

While plenty of horror movies attempt to be all terror all the time, directors Daniel Myrick and Eduardo Sánchez included a bit of humor at the beginning of their film.

"We'd had some screenings before, and usually when people laugh during the first sections of the film, we pretty much have them," said co-director Eduardo Sánchez during an interview with The A.V. Club.

A movie like The Blair Witch Project works best when it imitates reality; real life isn't completely serious, and the film mimics that injection of humor. Not only does this increase believability, but it also lulls the audience into a false sense of comfort. How can anything possibly go wrong if you're laughing?

Of course, when things do start taking a turn for the frightening, the audience is already invested in the film.

"Around the middle of the film, once things started getting tense, the audience was really still," said Sánchez. We'd look over and see people leaning forward in their chairs, staring at the screen, and we knew we had them. We had screened the film a million times, so we knew how things usually went, but it was pretty cool."

Today, we know The Blair Witch Project as one of the greatest horror movies of all time. But back when the film was released in 1999, audiences enjoyed a viewing experience unsullied by social media spoilers. The first viewers of the film were unsure whether what they were watching was real or fictional.

"You get a different experience when you go in [with no knowledge]," said co-director Dan Myrick. "It is enticing for us to entertain the thought of people going in there with no idea of what's going on, seeing [the film] for what it is and believing what's going on until they see the credits roll at the end. That's usually when we get the strongest reactions: people really believing it."