A bartender in 1920s Paris invented the Sidecar for a guy who stumbled in frozen after riding a motorcycle sidecar through winter streets—and somehow that desperate moment created one of the most perfectly balanced cocktails ever made. It's just three ingredients: Cognac, Cointreau, and fresh lemon juice shaken hard enough to frost the tin, but get the ratio wrong or use bottled lemon juice and you've completely destroyed a century-old masterpiece. The drink survives because it's actual liquid architecture where every element is load-bearing, and learning to make it properly teaches you more about cocktail balance than any fancy mixology class ever could.