A Bad Penny by Cat Stevens delves into themes of regret, repentance, and the consequences of one's actions. The song's central metaphor of a 'bad penny' represents a problematic or unwelcome situation that keeps resurfacing. Stevens uses this metaphor to explore how past mistakes continue to haunt and impact the present. Key moments in the song include the repetitive allusion to the 'bad penny' and the evocative lyrics about facing the consequences of one's choices. Overall, the song serves as a meditation on accountability and the enduring nature of past actions.