The Pleasant Surprise - Customer Experience Bliss and Word of Mouth Heaven

A recent study mentioned that over 1/2 of word of mouth is due to a pleasant surprise experience vs. expectation. What's that statement "underpromise and overdeliver"?

Stuff that isn't conventional makes people stop , digest it and play it back to others. Examples:

• Tiffany has the nicely wrapped blue box
• Doubletree Hotels has a freshly baked cookie
• Starbucks parades free samples of their new products on a regular basis
• The Soup Peddler delivers his product on a bike to your door step
• Charmin has created a portable theme park dedicated to toilet paper (sorry, bathroom tissue)
• Backroad Trips sends out personalized postcards with photos of your last trip
• My hairstylist always serves a well made capuccino or glass of wine before we get started on my mop of a haircut
• My local flower shop, delivers flowers on a retrofitted and ornately decorated motorbike
• I can get personalized M&Ms for any family occasion
• Certain bartenders etch my initials into the frothy head of Guinness
• Domino's has created a social network for pizza that informs, inspires and actually delivers too
• California Tortilla staff and customers play Rock, Paper, Scissors for discounts on menu item
• Labatt Blue used to put one of 30 replica Stanley Cups as an insert in their boxes
• Opus Hotel has the coolest music and hottest DJs flow right into their lobbies   
• A breakfast house in Vancouver (Elbow Room cafe) routinely insults its customers and provides rude service as a form of schadenfeude entertainment ( I was an unwitting victim once)

So what's your brand's surprise? And how much more will people pay for you because of it? And will they talk to others about it after it happens?  And will they return in hopes of gifting that same surprise on others or getting a different surprise?

For some inspiration, watch the attached video , it's hilarious and quite powerful to see people cope with stuff that exists outside their daily quotidian.