"When you fall down, get back up again" is a potential short story theme because it is a universal message that can resonate with readers. It is a theme that can be explored in various ways, such as through a character's personal struggles or a larger societal issue. The theme can also be applied to different genres, from drama to comedy, and can be adapted to different settings and time periods. Ultimately, the theme of resilience and perseverance in the face of adversity is a timeless and relatable topic that can make for a compelling short story.