A very pessimistic outlook:
People get by because they ignore things that make them upset at the world. I mean no disrespect towards religion, but that's how I've always viewed it; an explanation of our existence so we don't feel pointless. People who believe in a god always have someone who they believe loves them no matter what. Put simply, I feel like it's general delusion and dissociation from what is really happening in the world.
Another explanation could be faking happiness, though I'm sure if everyone on this earth were faking their happiness, more of us would fold and CTB.
Maybe it's a mix of them both.