“I remember every detail,” Rick (Humphrey Bogart) tells Ilsa (Ingrid Bergman) in Casablanca. “The Germans wore grey, you wore blue.”
The roguish American is talking about the last time the lovers were together – the day German tanks rolled into Paris. Until that point, Paris had been their romantic playground, the war a distant threat as they danced, drank and zoomed away from their cares in a convertible. In this extended flashback, they hatch a plan to meet at the train station and escape. Hours before they’re set to flee, Sam (Dooley Wilson) plays their favourite song – “As time goes by” – and they drain champagne to keep it from the Nazis while imagining their future. If Rick – who is grizzled, cynical and emotionally unavailable when audiences meet him months later in Casablanca – hadn’t been so blinded by love, he might have realised that when Ilsa said, “Kiss me. Kiss me as if it were the last time”, she meant it.
The only time Rick smiles in Casablanca is in this flashback sequence. In this idealic time he even jokes, aiming for genuine humour instead of the deadpan observations and wry asides he uses to evade the authorities and his emotions while running his seedy café in Casablanca. This is the Rick audiences know, the man who doesn’t “stick his neck out for nobody” and in an earlier scene has thrown a lover out of his bar. Part of his gruffness and guardedness (apart from being representative of America’s isolationist attitude in the early stages of WWII) comes from the wound he suffers when Isla doesn’t meet him at the train station, which happens just after she says the “kiss me” line – one of the most memorable in a film considered one of the all-time greats.
It’s that moment that turns Rick from a loving rake into a sardonic cynic and is essential to the man we meet in Casablanca. Despite what the lyrics to “As Time Goes By” promises – a kiss is just a kiss – that's not actually true, and the song is an ironic eulogy to their lost love, which the film cleverly hints at throughout the scenes they share in the present day.
While Casablanca is full of iconic (and misquoted) lines like “here’s looking at you, kid”, “this is the beginning of a beautiful friendship”, “of all the gin joints in all the towns...” and “play it, Sam” (not play it again, Sam), none are as important to the storyline as “kiss me”, the inciting incident of Rick’s emotional turmoil.