G is for Gravity Explained
Normally I would decry how dense and unobservant filmgoers are nowadays, but after absurd assfest of asininity that was F is for Fart several thought centers of even my brain were threatening to shut down permanently.
G is for Gravity opens, in first-person view, with a presumably male protagonist driving to the beach for one last ride on his surfboard. As he unloads his gear he places several bricks in a backpack, which he straps on (remember this, it's important later). He totes his board down the beach breathing heavily, probably nervously, possibly sobbing and enters the ocean and mounts up. He paddles out for a while until the water is sufficiently deep and then dismounts the surfboard.
Ah, but remember the backpack full of bricks? Their additional mass weighs down our protagonist and keeps him from surfacing again, whence he would find a breath of life-giving air. It seems GRAVITY made it so. Any doubt is washed away in the final shot of the surfboard's aft pointing skyward, opposite the combined mass of our now-dead protagonist, his backpack, and the bricks held in their position beneath the water's surface by the force of gravity.
M. Night Serling could not have pulled off a better twist, lest he was still alive or didn't start sucking.