Coming from Bartender a Paris and... uh, Bartender, Hisama's take seems to fly in the face of everything both of those series stand for, but I dig it.
Sometimes, a customer is just a customer. Especially on busy nights, it's simply not possible to read every single person to perfection and craft a drink specifically for them. When you can't do that, all you can rely on is perfecting your own technique, and continuously pushing it beyond what's thought to be possible. Of course, I would argue mixing whiskey and water for three days because you know someone's coming to order it is its own form of "crafting a drink specifically for a customer."
But, I think Hisama's general point makes sense. This author's series about bartending have always been human-focused first, and technique second, because their protagonists are assumed to be masters of their craft, so it's nice to have a reminder that being human-focused isn't an excuse for neglecting technique.