The people you see watching a play on a weekday night tend to appear fairly similar - roughly the same age, smartly dressed - if there could be such a thing as a 'theatre class', they would be it.
The first thing I noticed about the audience at The Curious Incident of the Dog in the Night Time was how varied it was compared to the usual crowd you'd see at Leeds Grand Theatre on a Tuesday.
There were pensioners, middle-aged people, parents with their young or grown-up children; teenagers, students and young couples. It was a mixed bag.
It mirrors the appeal of the book, which was released in 2003 and went on to win a string of awards, notably the Whitbread Book Awards for Best Novel and Book of the Year.
The central character, Christopher, has 'behavioural problems' which are never classified in the book but have been described as Asperger Syndrome.
He sets out to crack the mystery of what happened to his neighbour's dog, Wellington, who he discovers dead on her front lawn - stabbed with a garden fork.
While trying to find out who killed Wellington, Christopher manages to solve a much bigger puzzle he didn't even know existed.
The book is written from his perspective, and the reader is left to try and understand the other characters' feelings through the way Christopher perceives what happens to him.
Of course, on stage you can see his father's struggle to cope with his son's condition; the patience of his school mentor Siobhan while she's helping him to understand his feelings, and the frustration of other characters who come into contact with Christopher and his strange behaviour.
Joshua Jenkins as Christopher was brilliant - he's speaking almost constantly and there's so much energy in his performance - it's exhausting watching him.
The company takes a few parts each, as various neighbours, policemen, train passengers and pedestrians - my favourite was Roberta Kerr as Christopher's old lady neighbour Mrs Alexander.
When she walks back into her house to get biscuits and orange squash for Christopher, the rest of the characters move at lightning speed to demonstrate how slowly she shuffles - and it's one of many occasions where the performance turns into a piece of contemporary dance.
The set is made up of three giant grids, parts of which open to reveal hidden boxes; lights appear to show diagrams, star constellations and road maps - and when Christopher gets to London, you're enveloped in an audio visual assault of lights, pictures, colours and noise, starkly demonstrating how a busy, unfamiliar place must appear to him.
The stage adaptation premiered in London in 2012 and has since won seven Olivier Awards, including Best New Play.
It's an incredible piece of theatre: clever, moving, funny and sad all at the same time - and leaves you with a glimpse of the world through different eyes.
- The Curious Incident of the Dog in the Night-Time is at Leeds Grand Theatre until Saturday August 29.