Given the doubtful nature of English cooking, the Frenchman in me can certainly understand why you Brits cannot be gulled into taking seriously someone who expresses the wish that you enjoy your meal. He would, nevertheless, have thought that a conception of politeness which encourages you to display, from the very moment you meet, a maximum of congeniality towards your fellow man would, at least, require you to have the decency, on parting, to express the hope that he spends a pleasant day. Toutefois, when you think about it, what could be less astonishing that a people who for centuries were preached to night and day that enjoyment of any kind was a cardinal sin should rarely wish one another a pleasant anything?
Nevertheless, any serious-minded Francophile, keen to embrace French life to the full, must be aware right from the start that the Gallics find it impossible to leave those they’ve been chatting to without systematically wishing them a good something or other. The custom is such an institutionalized part of French lifestyle that not expressing the hope you have a nice walk or a good game of golf would be perceived, at best, as a glaring omission and, at worst, the height of discourtesy.
The most frequently-encountered of these turns of phrase are focussed on parts of the day or week : bonne journée, bon après-midi, bonne soirée, bonne nuit, bon weekend. Others (the untranslatability of which is proof they are alien to British culture) are more specific, and split morning, afternoon and evening into beginnings and ends: bonne fin d’après-midi (lit. have a good end to your afternoon), bon début de soirée (have a good beginning to your evening). And Bon réveil (Have a good awakening) is a favourite with early-morning newsreaders. What’s more, the custom can encompass any activity the other is, or soon will be engaged in, and the number of variants is, therefore, without limitation (I’ve even heard Bonne partie de puces (Have a good game of tiddlywinks). In addition, an all-embracing Bonne continuation (Continue to enjoy whatever you’re doing now) can be frequently heard.