Esher, your penultimate post was spot on. I can't think of any other retail environment where so many customers expect so much for so little. So many people seem to think they not only deserve a discount just for making a purchase, but also that small jobs are done free.
"How much? To fix a puncture? "
Yes. That much. Or you can do it yourself.
And then, to compound the problem, as heard in my LBS recently, "Thanks for your advice. That's going to help me when I order it online". ****.