One of the strongest truths in telling any story is that if you can’t make your lead characters likeable, at least make them interesting. Michael Corleone? Not likeable, but highly intriguing. Walter White? Really unlikeable, but dear God, so complex and endlessly fascinating. Darth Vader? One of my favorite movie characters of all time, but I certainly don’t like him in the least. In Gillian Robespierre’s “Landline,” the follow-up to her 2014 debut “Obvious Child,” there is nary an amiable character amongst the leads of the films, which makes for a difficult movie to watch or to recommend.