I have just had my boiler given its annual service. I paid the heating engineer and off he went. As I'm obviously bored this got me thinking. He provided me a service for which I paid him. In the real world I could leave him a reference on his website etc. Of course that is the real world.
Now in the internet modelling world he should leave me a reference. You know how it goes. Steve opened the door with a smile, escorted me into the kitchen and pointed out the boiler. Steve didn't stand over me as I did my stuff, but trusted me to service his boiler to gas safe standards. We had a chat over a cup of tea and discussed the price of gas and electricity.
I highly recommend Steve to other trades and look forward to servicing Steve's boiler in the future.
Of course the heating engineer might add, Steve paid promptly.