Biff is a lazy bum!…There’s one thing about Biff – he’s not lazy.

– Arthur Miller

Death of a Salesman, Act 1. Willy rails against what he sees as Biff’s failure to make anything of himself beyond a poorly paid farm worker, showing his own mental fragile state. One moment he is excoriating Biff as a "lazy bum" to Linda, while the next he says that his favorite son is not lazy. Willy’s self-contradictory nature is on display here.