Locke

A man walks into his car, and for the next 90 minutes- you are trapped alongside him. And you've no choice but to listen to his every word on the phone as he tries to salvage some semblance of a life, as everything he's ever had outside that car interior slowly dissolves and dissipates...

Amazing how quickly an hour and a half can go by with tight editing and good acting-  minimalism literally personified.

CAUTION:  Elicits High Risk of subject induced "relationship discussion" with significant other...