"This is what happens when people don't know the right amount to pay (how often do you call a locksmith?), so what they do is measure what they should pay based on the effort taken by the provider."
Except for that putting on a show is the key to success in almost every industry, whether you're an author, entrepreneur, salesperson, financial analyst, doctor, grocery store, etc. In fact the only area I can think of where this isn't the case is in amateur sports, which is telling.
If I go to the grocery store and the cashier takes twice as long to ring me up as normal (all the while sweating and looking like he's trying very hard) I don't count it in favor of the cashier or the store. The reason is that I know how long it's supposed to take to ring me up, and this cashier is just bad at it.
On the other hand, I have very little understanding of how much time/effort is required by doctors and financial analysts, so I could easily be tricked by them.
That's not how grocery stores put on a show. They do it by doing things like spraying the vegetables with mist, even though it doesn't do anything to help them stay fresh. And by making the floors look immaculately clean even though whether or not the floors are scuffed up has zero to do with food safety. And of course Asian food stores do the exact opposite; they make their stores look cluttered and dirty on purpose, which signals to their customers that the staff is hard working and their food is fresh and cheap.
I, and I think most people, factor the time it takes to check out into the price I'm willing to pay for goods. This is supported by the fact that grocery store managers will often stop whatever they are doing to open new checkout lines whenever they are getting full.