At the start of the play, Biff has just returned home. He and his brother Happy mull over their lack of success and fulfilment in life; Happy chafes at being kept under in his low-paid office job in the city, while Biff has no settled work. He describes to Happy his latest spell working on a ranch out West:
This farm that I work on, it's spring there now, see? And they've got about fifteen new colts. There's nothing more inspiring or - beautiful than the sight of a mare and a new colt. And it's cool there nowm see? Texas is cool now, and it's spring. And whenever spring comes to where I am, I suddenly get the feeling my God, I'm not getting anywhere. What the hell am I doing, playing around with horses, twenty-eight dollars a week! I'm thirty-four years old, I oughta be making my future. That's when I come running home. (Act 1)
From this quote, we can see that Biff feels particularly restless in springtime, which heralds the blossoming of nature for another year (symbolised here by the mares and new colts), a time of new beginnings, a chance to start afresh. However Biff realises that his own path has stagnated, he doesn't have a proper regular job, he's making hardly any money, he's simply 'not getting anywhere'. This panicked realisation has brought him home, but once he arrives, he still remains without any direction, without any idea of how to build his life, his future. As he says himself, he is acting irresponsibly, he has no career and he's not married; he's 'just like a boy' (Act 1).
Biff has become confused as to what he really wants from life and how to go about it. This stems from his failure in high school, his unexpected discovery of his father's infidelity (which he never reveals to anyone else) and his father's unrealistic notions about how to get on in the world, which he is forever trying to impress on his sons. Biff has come to resent Willy and to blame him in large measure for his own failures.