10 Intense Movies That Dared You To Sit Through Them

Primer isn't intense because of its breakneck pace, explicit violence, or disturbing subject matter - in fact, it's the opposite of so many movies on this list.

Generally speaking, the sci-fi flick is the story of two boring white dorks who accidentally discover time travel. They don't use this technology to go back in time and stop Ryan Reynolds from making Green Lantern or anything as extravagant as that either: Primer a low key tale with comparatively low key stakes.

So why is it on this list? Well that's because what the movie lacks in thrills it more than makes up for in extended scenes of the two characters figuring out the science of the device they're creating.

Rather than handwaving away the intricacies of the time travel machine to get on with the story, the time travel machine is the story, and as such the film spends a huge amount of time detailing the exact scientific theories and equations behind what's happening.

Consequently there's going to be a good chance that you'll quickly get lost in the jargon and the logistical specificities, as Primer has no interest in simplifying any of it.