service provider: “Hello, I’m a window cleaner, do you want me to clean your windows? I’ll actually do it for free this time! Please recommend me to your peers”
customer: “yes please”
service provider: “all done! Want me to do it again in three months time?”
customer: “yes, I love free stuff!”
service provider: “actually, I’d have to charge for that, can’t work for free all the time.”