Her (2013)
A lonely Theodore Twombly (Joaquin Phoenix) begins to see futility in entering relationships in Her (2013).

Have you seen the film Her (2013)? We recommend it to you. It will shake you up and make you doubt what it is to be human and what it is to love. Wait, why would we recommend it then?! I don’t know. Anyway, here is a taster for your pleasure:

'The room's spinning right now 'cause I drank too much 'cause I wanted to get drunk and have sex 'cause there was something sexy about that woman and because I was lonely. Maybe more just 'cause I was lonely … and I wanted someone to f*** me. And I wanted someone to want me to f*** them. Maybe that would have filled this tiny little black hole in my heart for a moment. But probably not. Sometimes I think I've felt everything I'm ever gonna feel and from here on out I'm not going to feel anything new—just lesser versions of what I've already felt.' — Theodore Twombly (Joaquin Phoenix)

Watch it and see what you think. (In hushed tones: ‘Embrace the sadness.’)