Never Put It in Writing (1964)

While in Ireland, a young insurance executive finds out that back at company headquarters, someone else has been promoted to a job that he was hoping to get. Enraged, he writes a scathing--and insulting--letter to his superiors. He soon discovers, however, that the reason he wasn't promoted was that the company is going to promote him to an even more important job with even more money. Frantic, he desperately tries to get the letter back before it gets to his bosses.