Dad – I let you down.
– Arthur Miller
Death of a Salesman, Act 2. The young Biff arrives at his father’s Boston hotel bedroom door with a suitcase in hand and says this to Willy. He feels that he has disappointed his father because he has failed math. Biff’s words are ironic, because it is Willy who has betrayed and let down Biff and the family by cheating on Linda with a woman he has in the room.