I'm not citing this as an example of my brilliance by a long shot, nor do I wish to brag by this. Hopefully you may learn something from this experience though... I think I have.
At work I've had to deal with a particularly nasty person. They're extremely slow in paying bills (they always go at least 120 days from the invoice being sent) and when they do want something done, they will complain until they're black and blue in the face that they want the work done now, they want it done tommorrow or they want it done yesterday. They demand some of this, less of that, and plenty of that and tommorrow their demands will have changed so we'd better stay awake.
This particular person is a real estate agent and on the whole they're not known for their luminence of character; especially this person.
It came upon us that one of their clients wanted to get some background information on them. Owing to confidentiality requirements (because if you can't tell someone in confidence, then they aren't worth knowing), I told this person that our real estate agent friend was a skilled operator (which although is true, doesn't mention anything about their character) and they went away happy. The truth is that the job would be done very well, even if they don't see us as particularly important.
Not long after this, I wrote to the estate agent and told them that I'd slashed their latest invoice by 8% and then enclosed a voucher for two people to go to quite a nice restaurant in Mosman. My boss thought I was stark raving bonkers and wanted to know what possessed me to do such a crazy thing and I told him that if we showed a little bit of kindness to our most difficult clients, despite and in spite of them being a persnickety ogre, then even if we get nothing back then at least we may have warmed their heart of ice a bit.
People find it very very difficult to be nasty to someone who's just been nice to them. It was once said of Eleanor Roosevelt that she got even in a way with someone that was almost cruel, she forgave them.
There is a famous story of the sun and the wind having a competition to see who could take the coat off a man. The wind blew and blew but the man held his coat even tighter. It blew even stronger and the man hid behind a tree to get out of its way. But the sun shone warmly and gently and the man who was now warm, took off his coat without complaint.
I don't mean killing someone with kindness either, but at some point you just realise that repaying what you got only escalates it, be it violence, kindness, apathy or dare I say it love.