I can kinda feel what you're getting at. The value of currency essentially only comes from a chain of beliefs about the value of the currency. In a world where governments can print currency, the value becomes more and more of an abstraction as compared to any kind of value that is linked directly to a material quantity. This is part of the reason cryptocurrencies were invented, so that there is less government shifting of the ground under people's feet.
At the same time, I often appreciate that the use of things like fixed prices mean that every customer gets the same treatment, regardless of our personal relationship towards the seller. To me, it seems like a fairer world where being friends with the seller, or being a skilled haggler or whatever have no effect on the price, and instead, the price is the price.
I also feel that it is better when prices are lowered according to need - people without the means to pay receiving cheaper or free medical treatment, for example.
In contrast, on the broader scale of things, the ability to lower prices based on "We like each other." seems much more unfair. After all, someone with a lot of money doesn't need the prices to be lowered.
I guess what I was reacting to were the inklings of a B.F. Skinner-ish behaviourist attack on individual autonomy and free will.
Anybody who adheres to that needs to read Karl Popper, and then throw their gnosticism in the trash where it belongs. Terrified of uncertainty? Too bad. It isn't going away, no matter how much you or "we" "optimize".
The more that mistake theorists proclaim themselves as wiser and "criticize democracy...because it gives too much power to the average person", the more conflict theorists (extremists, Trump voters, etc...) they will nurture.
For an example of what I meant: it seems that it would be far easier to write a guide on how to bake a cake or complete an equation than it would be to write a guide on performing 5 minutes of stand-up comedy that an audience would appreciate.
If this isn't related to how much of a rational process such a thing is, how else would you explain it?
Attraction, humor, joy and love are very often irrational and arbitrary. They are also some of humanity's favorite things. Depending on who you ask, these things also often feel the best when they operate outside of materialistic or coldly utilitarian ends.
As to how this applies elsewhere - interviewers conducting a job interview are often potential future co-workers, right? People liking each other is a good predictor of co-operation. Thus, candidates are often measured against "fitting in with company culture" in this way.
So, if increased co-operation is "optimal", yet "likability" stems more from subjective arbitrary feeling than rational criteria, then our process of determining what is "optimal" is not, and perhaps should not be simply derived from what is most rational.
From another perspective, there is this: The double thank you of capitalism.