Bruce Willis is sent back from the future to try to isolate the cause of a pandemic that has caused most of civilization to live underground -- he won't be able to stop it, but maybe they can develop a cure or a vaccine. His time travel mechanism isn't perfect, so he's jolted around to different times, causing him to miss what the cause is until too late, but at least we get some wacky Brad Pitt along the way. Makes you want to get your flu shot.
You might also like: "Contagion"
Fertility failure: "Children of Men"
The last child was born was 18 years ago, and humanity has finally come to terms with the fact that there will be no more children -- until a woman quite miraculously gets pregnant. Clive Owen is entrusted with protecting her and delivering her to some scientists trying to cure infertility, the Human Project. Her baby could be the hope of the future. Makes you want to procreate.
You might also like: "The Handmaid's Tale"
Religion: "The Rapture"
It's in the Book of Revelation -- the End of Days. Mimi Rogers goes from swinger to born-again Christian (with some help from David Duchovny), and believes God's judgment is coming. She goes to the desert to wait for the Second Coming, and growing impatient, kills her daughter and tries to kill herself. And then the Rapture actually happens, much to her dismay. Makes you want to pray.
You might also like: "Dogma"