The song "Mr. Brightside" by The Killers is about a man who is dealing with feelings of jealousy, paranoia, and heartbreak as he suspects his partner of cheating on him. The lyrics reflect his torment and emotional struggle as he observes or imagines his partner's infidelity. Despite this painful situation, the title "Mr. Brightside" suggests he is trying to stay positive or look on the brighter side amid the hurt. The song captures the emotional intensity of suspicion and heartbreak, making it an anthem for cheated hearts and those grappling with jealousy.
The song was one of the first written by the band members Brandon Flowers and Dave Keuning and has become the band's best-selling song. It has resonated widely due to its energetic music that contrasts with its wistful and painful lyrical premise.