Precious

Give Mo'Nique the Oscar.

While Precious is not the downer it appears to be on the surface, there are some very dark elements. We follow Precious through her life where all odds are stacked against her while she dreams frivolously of beautiful things both she and you as the viewer know are never going to happen.

It's powerful stuff and realistically presented. The antagonist is her demon of a mother played by Mo'Nique. At the end (don't worry, not a spoiler) as she is explaining her life to a social worker, Mo'Nique absolutely steals the entire show and leaves you numb with horror and grief. But, again, don't worry - Precious is the light.