I'm Sorry (in the Future) (1970)

Sinopsis

A film about the minor pains in life... and the major ones too. Upon learning he is to be a father, Brent types a letter to his impending child detailing how pain, no matter how small and insignificant, will be part of their life. A kaleidoscope of comedic violence ensues, eventually leading to the source:a painful memory that will forever shape Brent's own life.