Every verbal exchange in France starts with a mandatory passport: bonjour during daylight hours, or bonsoir once dusk approaches. English speakers treat greetings as optional pleasantries that can be bypassed when getting straight to business. In French conversational norms, bypassing the greeting strips the other person of their dignity as a social equal.
When you walk up to a bakery counter in Bordeaux and say, "Merci, une baguette," the baker does not hear friendliness. They hear an aggressive truncation of basic manners. The rule holds without exception across service encounters, train stations, and hotel desks. You must say "Bonjour, Madame" or "Bonjour, Monsieur," pause to allow them to respond, and only then proceed with your transaction. Gratitude belongs strictly at the end of the exchange, functioning as the seal on a completed human interaction rather than a lubricator at the start.
