I Knew You Were Trouble by Taylor Swift is a pop song that delves into the emotional turmoil of falling for someone who eventually turns out to be bad for you. Taylor recounts the story of being attracted to someone she knew was trouble from the start. The key themes include heartbreak, regret, and self-awareness. Particularly poignant moments in the song include the realization of betrayal and the internal conflict of knowing the risk but still falling for the charm. The song addresses the painful lesson of hindsight and the impact of allowing oneself to be vulnerable.