According to golf etiquette, why do you have to wish your flight partner a "nice game"?
You wish your fellow players a "good game" at the start of the round of golf on the first tee. This kindness is part of good etiquette among golfers and is part of proper golfing behavior. It is a way of showing your fellow players respect for their presence and the upcoming round together. Wishing a good game is comparable to saying "good luck" when fishing, for example. The term "good game" has now also become established in other sports, for example the referee often wishes both teams in soccer. However, golf in Germany can certainly pride itself on having translated and coined this term.