The dad in The Princess Bride isn't even in the film, but I think the movie fits the Dads in Media Blogathon theme anyway, because the dad drives the major subplot.
"Hello. My name is Inigo Montoya. You killed my father. Prepare to die." Ever since he was scarred for life at the age of 11 trying to kill the 6-fingered man who had just murdered his father, he has sought the man. His thirst for revenge has driven him for 20 years. The scene in which he comes face to face with the killer has the killer begging for mercy, offering Inigo anything he wants. Inigo responds with this cry: "I want my father back." Some things can't be replaced.
Here's that part:
We had seen the play in a children's community theater performance years ago but had not seen the movie until tonight. It was fun.
New York Times