The Heart's a Wonder (1978)

The film is based on John Millington Synge's play The Playboy of the Western World. Christy Mahon comes into a pub and boasts that he has just killed his father. Instead of condemning him for the crime, the locals revel in his story and praise him for his deed, with the daughter of the landlord falling for this "dashing hero". Things take an even more surprising turn, when Christy's father enters the pub.