Cocktail Ingredient Substitution Guide

You find a recipe, gather your bottles, and realize you're missing one ingredient. The internet tells you "just use X instead" - but X ruins the drink. The problem isn't that substitutes don't exist. It's that most advice ignores context.

Swapping lemon for lime in a Margarita is a minor tweak. Swapping sweet vermouth for dry vermouth in a Manhattan is a disaster.