The Law of Reciprocity is as simple this: do something nice for a decent person, and they'll want to return the favour.
It's one of my favourite universal laws and I see it in action all the time.
Nowhere better than this hand written card I received around Valentines day from a local Beauty Salon I've never before patronised.
The card says "Happy Valentines day Kirsty. The team at Beauty Plus have selected you as one of the hardest working women in Launceston. We wanted to reward you with a free 30 minute massage...."
Instantly. I know this salon. I remember this salon. I feel good will towards them and all they've done so far is compliment me and offer me something that will cost them half an hour of one staff member's time - but could lead to a long term customer (and in this case, one who talks about places she loves a lot).
Limited cost, big potential payoff. I love it. And the law of reciprocity means I'm unlikely to take them up on their half hour massage offer and spend nothing else with them. It also means that they've wowed me enough that I'll share the story and give them positive word of mouth that way.
And for the cynics out there who know that I'm unlikely to have been the only person to receive a card for Valentines Day - you know what, it doesn't matter! Provided they haven't gone overboard and my entire facebook feed is teeming with Launceston's "hardest working women" - the recipient, me in this instance, can still smile and feel special - and let the law of reciprocity do it's thing.