"Here's looking at you, kid" — Casablanca (1942)

Humphrey Bogart's parting words to Ingrid Bergman in Casablanca distilled an entire romance into five syllables. The line was partly improvised during production — Bogart had used it while teaching Bergman poker between takes. It topped the AFI's 100 Greatest Movie Quotes list in 2005 and remains the most romantically resonant farewell in cinema history.