Smile Like You Mean It by The Killers is a poignant reflection on the passage of time and the inevitability of change. The song captures a sense of nostalgia and longing for the past, as the narrator looks back on significant moments in their life with a mix of melancholy and acceptance. Key themes include the fleeting nature of youth, the impact of choices made, and the bittersweet nature of memory. Particularly poignant moments in the song include lines that evoke a sense of loss and introspection, reminding listeners to cherish the present and 'smile' genuinely, despite life's challenges.