Logan's Run, Soylent Green, Mad Max, Gattaca, 1984, Equilibrium, Idiocracy, Children of Men, Fahrenheit 451 (though that one reminded me too much of Dr. Who), The Island, and Wall-E.
They do not make me fearful of the future because I find part of the philosophy behind them flawed. For one I believe in rebellion. As long as there are teenagers on the planet there will be rebellion, and thus someone undermining the system. Secondly, there is a streak of contrarianism that flows though many of my associates and friends, which makes me believe that whatever grand scheme a government, super-corporation, Baptist theocrats that manage not to break up after the first year (Handmaid's Tale), or other large power that takes over the whole world, will be challenged, undermined, or ignored. Brave New World had the Savages, Fahrenheit 451 had the folks out in the woods reciting books to no one in particular, Gattaca had the love children (people who were not genetically designed), and so on.
The environmental hellfire and brimstone tv or cinematic bits showing a hellish Waterworld (yes, I watched it), or NYC of Soylent Green have their own problems. Humans are wonderfully adaptable. Yeah, a whole bunch of us will die off with any great change. But there are Eskimos (can't spell the proper native name) in the Hell I call Alaska and northern Canada, Aboriginals in the Outback, Arabs in the desert, Isrealites in the desert, and other people in places that are too cold, too hot, and just plain crappy.