BIFF: He’s off salary. My God, working on commission!
HAPPY: Well, let’s face it: he’s no hot-shot selling man. Except that sometimes, you have to admit, he’s a sweet personality.

– Arthur Miller

Death of a Salesman, Act 1. Biff and Happy discuss Willy’s loss of status at work where he has been demoted and is soon to be fired. It is clear that they realize their father is not as good a salesman as he is made out to me.