The Weirdo (1989)

Donnie Raymond is a typical weirdo; a mildly autistic, shed-dwelling loner living in Los Angeles who is looked after by a kindly elderly woman named Miss Martins, who is his adopted mother.

Lisa, Miss Martin's niece, comes to visit and is told to stay away from Donnie, who begins doing volunteer work at a local church where he meets an equally troubled teenage girl named Jenny, who becomes smitten with him and the two start a tentative romance. For the first time in his life, Donnie thinks that he has a purpose and is happy, but this is very short-lived. After years of torment and torture by his estranged mother, three neighborhood punks and their girlfriend, rejection and attempted eviction from the shed by Miss Martins, and scolding by the neighborhood cleric Reverend Cummings and the reverend's wife, the young Donnie snaps and takes out his frustration with society in particularly violent ways.