Surprise and pleasure?

When can unfulfilled expectations cause a smile?

I've recently been moving further into stand-up comedy, diversifying from the situational comedy which is my main work. While reading up on gag writing, I stumbled across this statement by stand-up guru Basil White:

"We know people assign expectations to an experience while they're still having the experience. We know that when people become aware of how they assigned the wrong expectation to an experience, the brain gives us a pleasure response that makes us laugh."

There is some very "experiential" language in there. Coincidence?

Basil's words got me thinking. I've always been a firm believer that the easiest way to make a customer happy is to give them more than they expect. We also know that surprises - even simple ones like suddenly appearing or disappearing - are an old slapstick tradition. I wonder how the themes surprise, pleasure and customer satisfaction (or, more interestingly, customer sacrifice) interrelate? What is the brain circuitry or conditioning behind it?

Of course, there is a difference between comedy and service design here, as customers invest more than audiences do. Their investment allows them to demand pleasant surprises - you're not going to gain a lot of fans by pouring icy water down the customer's trousers at the checkout. Mind you, they might enjoy it if your trousers were the ones getting the soaking.

So, some thinking homework for everyone - what function should surprise have in customer experiences?