Hot N Cold by Katy Perry is a pop anthem dealing with the unpredictable nature of a tumultuous relationship. The song addresses themes like inconsistency, emotional instability, and the frustrations that arise from a partner who is hot one moment and cold the next. Key moments in the song include lines like 'You change your mind like a girl changes clothes,' highlighting the erratic behavior of the partner. Through catchy lyrics and a vibrant beat, Perry encapsulates the roller coaster of emotions tied to loving someone who is unreliable.