God Bless America (2011) on Netflix

Divorced Frank Murdoch is dismayed by the state of American culture, where being mean and/or inconsiderate are often valued and rewarded, as shown by the plethora of reality television stars who are given their own highly paid public and celebrated forums to act this way. His own act of what he considers kindness does not result in what he expects. Although he loves his adolescent daughter Ava, she often throws tantrums which are supported by the way Frank's ex-wife treats her. On top of everything, he suffers from insomnia and migraine headaches, which are exacerbated by the actions of his inconsiderate neighbors. When he receives a terminal brain tumor diagnosis which is the probable cause of the headaches and insomnia, he decides to kill one of the people who he feels contributes to this cultural decline, before he takes his own life. But following that murder, he meets high school student Roxy Harmon, a product of an unloving home life, she who convinces Frank to continue his murdering ways with her as his partner. Unlike Frank who wants to remain anonymous while the world knows why these people were murdered, Roxy wants to kill anyone whose beliefs she does not agree with, and wants the notoriety from the killings. The question becomes how long this odd couple can survive together with their slightly divergent reasons for doing what they're doing.