You Don't Know Where Your Interest Lies by Simon & Garfunkel explores themes of self-awareness, manipulation, and the complexities of romantic relationships. The song speaks from the perspective of someone who attempts to enlighten their partner about their misguided interests and intentions, suggesting that they are being used and misled. Key poignant moments include the emphasis on self-discovery and the blunt observations made by the speaker in an effort to reveal the truth to their partner.