I would think that the shop would benefit simply by honoring their word to take care of it with no charge.

I want to use this shop in the future to build up a bike (or two) from the box at their going rate, discount or no.

My impression as I said before, is that they consider customers a "necessary evil." They need our money, and need us to come in, but every second we spend with them is time off the clock. So, they want us to come in, but don't want us to say anything or do anything besides pay and leave immediately.

Unfortunately, even the very fact that we come in at all is considered a "disturbance" and upsetting to their work flow.

Their margins must be really tiny for them to be in a such a mood.

My guess is that they aren't satisfied with their earnings and take it out on their customers.

The market has set an equilibrium price on bicycle labor, and apparently they aren't very happy with it.

What's strange is that when I came in for derailleur adjustments, they insisted more than once that the rear didn't require adjustment. I was offering them more money and they nearly refused! Fortunately it worked out since the shifting did improve (I was happy), and they made a bit more money (they were happy, I think?).

They are happy and upbeat on the phone, then upset when they actually see you, get upset when they are asked to honor a no charge adjustment, and then argue with you if you want to pay them more than is necessary?

These guys are just setting themselves up to fail, or at least to feel bad about their income and customers with all of these contradictions.