The world of cocktail creation isn't as simple as ordering a drink between adrenaline-pumped car chases in a plush casino setting, just as your favorite spy does it. Instead, there are rules and norms to be followed, especially when it comes to the shake-or-stir debate. Spirit-heavy cocktails like the classic Martini and Manhattan are typically stirred, while those featuring fresh juice and egg white, such as Daiquiris, Margaritas and sours are generally shaken.

Why? When shaking a spirit with fruit juice and ice, the ingredients emulsify, resulting in a frothy and fully blended cocktail that’s more satisfying than a stirred mix. However, tossing spirit-dominated cocktails around with ice in a shaker might over dilute them and cloud their appearance.

Branden von Fugate, a Southern California bartender and consultant, author of "This is a Cocktail Book", explains that stirring a spirit-only drink with ice helps to create the desired drink dilution and the perfect “mouthfeel”. Shaking such a concoction disrupts its smooth texture and mingles its intricate tastes under a froth, fogging up its appearance. His point comes to life with a simple demonstration using two Manhattans - one shaken, one stirred. The shaken version loses the essential elements - the fruitiness of the vermouth and the whiskey’s vanilla/caramel middle notes.

Yet, as with any rule, there are exceptions, and such choices often boil down to personal preferences, driven by factors like how chilled or strongly flavored you want your cocktail. Patty Dennison, head bartender at Grand Army in Brooklyn, New York, mentions that she would shake a stirred drink if the circumstances call for it to be tremendously cold. In everything from a Dirty Vodka Martini to a classic Martini enjoyed at a steakhouse, context matters.

Shaking has been the default cocktail preparation method, not just for its efficiency in chilling drinks quickly, but also the theatrical spectacle it brings-the dramatic mash-up of rhythmic ice against the tin. However, movie depiction is not equivalent to authenticity, as seen with 'Martini shakers'.

Certain cocktails, like the fan-favorite Espresso Martini, insist on being shaken despite containing no juice, simply because it brings the drink to life. Conversely, cocktails with cordials, like a Gimlet made with fresh citrus cordials, may taste better when stirred. The Stinger - a whimsical mix of Cognac, and crème de menthe - impresses best when served with crushed ice, balancing its otherwise unorthodox mix efficiently, while creamy cocktails like White Russians transcend their simple stir-to-serve method when shaken, resulting in a rich, velvety delight.