A few years (ah, decades) ago, my mother was on holidays in Turkey.
At a market, she inspected some kitchen knives and chef's knives (mindful of my howls about how poor, and blunt, and wretchedly crafted the knives we had at home, at the time, were), and asked the vendor whether they were sufficiently sharp for her (my) needs.
By way of answer, he extended a hirsute arm, and proceeded to slice some of the hairs from his arm with the chef's knife held steadily in his other hand.
That (impressive) demonstration sufficed, and she arrived home with a number of rather good blades and knives, some of which I still use.