"He has got a good ear for the vernacular. He writes in a way people speak not how you read."
The scene for Four Flat Whites is set when retired librarians Alison and Adrian excitedly plan to embark on their long-awaited, and carefully saved for, Italian holiday.
But when their best friends pull out at the last minute, they find themselves sharing their precious holiday with their neighbours - Harry, a wealthy plumber and his new wife Judy.
As these mismatched couples valiantly negotiate the pit-falls of a later-in-life OE, it's not just the Italians the intrepid travellers have to deal with - it's also each other.
"The two mismatched couples find they have more in common than they realise. They wouldn't normally be associating with each other - the couples are stalwart red vs blue politically," said Grieve.
"We are flushing that out in the scenes. It's that old thing about don't judge a book by its cover.
"People you might think are not on your side, are actually at heart good-natured people. As Kiwis, we are not that diametrically opposed. We give politicians about nine years and then give the opposition a go," he said.
What: Four Flat Whites
Where: Civic Theatre
When: Sunday 4pm - 6.30pm
Tickets: Ticketmaster