If you can be friendly, helpful & confident that what you are doing is lawful - you should be generally assured in return - of co-operative and helpful responses from the authorities.
NZ Border Protection (CUSTOMS)- But not always..
I have occasionally met with a panicked response from Customs personnel when faced with a situation that they have not been trained for .. both here in New Zealand and in Australia.
Four times now I have seen young International counter staff 'blanch' and even hit the panic button when told that I was carrying firearms ! - The color drains from their face - only for it to then become flushed as they defensively step backwards and stare wide-eyed.
I believe that these poor things were likely part-time casual staff engaged at peak traffic times to process routine holiday travelers - on each occasion the arrival of the professionals broke the tension - "Oh hello Martin - we've been expecting you to arrive."
On one occasion I was requesting an export 'Sight-Out Form' for a pistol barrel (for taxation purposes) at the airport Customs Office - and was belligerently informed by a young guy that this was illegal and that all handguns were banned! - I just sighed and tried to smile while asking for his Senior Officer.
You know how it is - if a big dumb bumble bee gets trapped inside your windows - you could squash it and make a sticky smear on the glass - but could be much better to kindly help it find its way out of the situation eh.