Tony Steadman
Tony is the protagonist and lead of the play. He has just turned forty, and he's feeling his age. Painfully self-conscious of his lack of accomplishment, Tony indulges a little self-loathing on repeat before deciding to try to accomplish something again. After his vairous failures, the most profound detail of Tony's character is how he values himself so poorly. He celebrates none of his work, none of his attributes, and none of his relationships. Looking back, Tony only sees failure. His ultimate goal in life is fame and fortune, so any attempt which didn't lead there he views as unnecessary and a waste of time. Consequently, Tony adopts the idea that his entire life has been a waste. By the end of the play, he comes to re-examine how he values his own life after Nick's threatening interference with the status quo.
Nick
Nick is Tony's friend, a recent friend at that. The two of them haunt the same local pub. While he's a great drinking companion, Nick is not a good friend. Rather than encouraging and challenging Tony to re-frame his life story, Nick leans into the indulgent self-pity and even piles on more shame for his friend. After Tony tries once more to do something he finds meaninful with his life, Nick is all too eager to welcome Tony back to the pub. He uses Tony as an outlet for his own pent-up aggression, unwittingly offering the most compelling evidence that Tony needs to change, if only to find better friends.