Some things are made real only through agreement of many people and no one believes it can be changed. Those things are made up concepts that is considered unquestionable “normal” or “natural” and “how it has been and always should be”.
The positive effect of this is that it brings stability and trust in that these things, even if we can not see or touch them, will still exist. Ten dollars is ten dollars and never nine dollars whatever it’s exchange rate.
The negative is that it strongly inhibits change. Like Saturdays. They do not exist, there is really no such thing as Saturdays, it’s just another indistinguishable rotation of the Earth relative to the Sun. But even if everyone would want another Saturday in a week instead of, say, a Wednesday, it’s extremely difficult to change, though not impossible.
If enough people agree to lift The Veil of Coherence we could have two Saturdays every week.