Tipping, etiquette, the rules nobody tells you

You're off somewhere new and the worry isn't the flight, it's accidentally being rude over dinner. This briefs you on the place's social customs, the tipping norms, the things a Brit does by reflex that land badly, and three useful phrases with rough pronunciation. For the trip where you'd rather not be the obvious tourist who got it wrong.

Brief me on [country or region] social customs, tipping norms, what is rude that a Brit might do by accident, and three useful phrases with rough pronunciation.