I can't believe people call professionals "nitwits" and "dumb". New Zealand immigration and customs (different things folks) are very polite. Actually I only found polite officers all around the world, even with questions that sound stupid - they're trying to find a needle in a haystack.

UK officer when I moved from one terminal to another, looking at my New Zealand passport where it says "Born in [city] [Brazil]:

 

• "Are you travelling with your NZ passport only? You don't have your Brazilian passport on you?"
• "No, I don't have it on me."
• "Ok, thanks"

NZ officer looking at my passport AFTER I have passed the immigration back into the country:

 

• "How long you have had NZ citizenship?"
• "[Number] years"
• "Thanks, welcome back"

AU officer when I go through with carry on bag and don't stop at baggage claim:

 

• "No suitcases?"
• "No, day only trip."
• "Thanks, have a nice time in Sydney."

US officer when going to conference in Vegas:

 

• "Visiting Vegas for pleasure or conference?"
• "Conference"
• "Great, have a good time, it will be full there"

In other words, Weathon's Law applies: Don't be a dick.