It's the opposite journey from what I've usually done with films. I find it very easy to go from, say, a lit, pleasurable environment, like what you see outside there, to a very dark place. But the opposite journey, which is what this movie takes, is much more complicated.
People could rationally decide that prolonged relationships take up too much time and effort and that they'd much rather do other kinds of things. But most people are afraid of rejection.