Like any people, New Zealanders have their own habits and quirks that are worth knowing about before you arrive, in order to avoid embarrassing situations during a stay in Kiwi country. But don't worry - overall, our ways of life are pretty similar.
If you are naturist, or even if you just like going topless, you should note that this does not go down well with the Kiwis. I therefore recommend that you pack a bathing suit as a result! On the other hand, avoid sitting in places where food is prepared, or on tables or desks where people write - that's not appreciated either.
You will be surprised to note that nobody does anything for pedestrians in the country, and you'll never see a car stop to let you cross: if that does happen, just assume that there's a foreigner behind the wheel! Effectively, pedestrians never have right-of-way, except when there is a sign that says so - which is rare, trust me!
In conclusion, it is important to remember that New Zealanders are extremely sensitive toward nature and that they protect their environment. You should therefore understand that leaving trash at the side of the road, polluting, or throwing stones at animals is not tolerated in any circumstances. In fact, I saw a man get arrested for throwing pebbles at ducks in a park!
Oh yes, I almost forgot.... try to avoid annoying New Zealanders by mixing them up with Australians!
When you walk into a store, don't be surprised if the clerk asks you lots of questions, some of which can be very personal., such as "What are you gonna do today?" unless you seem too lost in the moment. In fact, New Zealanders are very quick to strike up a conversation and showing interest in the customer is just a question of politeness. My experience of working in the country helped me to understand that all bosses expect their workers to have a conversation with customers, and not to make do with "Hello, how are you today?"
Many Maori sites are sacred, and you may need to get special permission to take a photograph, or even to enter the site at all. Make sure that you find out in advance about the rules that apply. For example, you sometimes need to take off your shoes before entering a room.