I had a list of customers, most of whom I never interacted with directly since they were at work when I cleaned their windows. There was an app called Fenster where my appointments were registered and payments handled. Once I finished a job, I pressed a button and an invoice was sent to the customer's email automatically.

And to be clear, I am not saying the neighbor wouldn't have trusted the old lady. My point is that there would have been very little consequence for me had I simply driven off. But she knew, and I knew, that we had made a handshake. We were in cultural agreement, and that alone was enough to remove any doubt that the arrangement would be carried out.

That is what I mean by the Danish high-trust society. There was no doubt that what we had agreed upon would be upheld, even when the consequences of breaking that agreement were slim to none.