@socketwench - The Planet of the Apes films are my go-to for when I've lost faith in humanity and am genuinely in a lousy mood. Cause none of the movies end on a good note.

Conquest is freaking great, though. A sci-fi version of the Watts Riots. The budget is threadbare, but it really pulls off the riots well. Sadly, the ending was tweaked to weaken the movie...but at the same time, the original ending is out there and worth seeing.