Do we need more service-industry tell-alls?

Leonard Lopate informs us that there's a new book out, a dramatic tell-all in which it's revealed that hotel staff prefer polite customers who tip. Another service-industry confession, in other words, a genre that can only hold out for so long. After all, most of us don't reach adulthood without having some job during which we learn that behind whichever pristine façade is work, filthy work. (The worst I learned first-hand was that your regular coffee might actually be decaf - which I'd have guessed - but I wasn't in food-service for long.)

From what I can tell, the revelations in any such confession are limited to the following:

-People like it when you give them money.
-Do not go to people who work X job to ask what a normal/acceptable tip is for someone in that position, unless you want to be told some inflated nonsense. (I'm looking at you, waitstaff who claim a 30% tip is standard in NYC restaurants.)
-They may smile and act all friendly, but service-industry workers are not helping you out of the goodness of their hearts. They are not your actual friends - unless, you know, they happen to be people you're friends with.
-Service-industry workers, like other human beings, are 'on' at work, but when 'off,' or when out of sight, engage in non-work-appropriate behavior.
-Things you yourself didn't clean/cook are less hygienic than ones you did.
-There's random bodily this-and-that where you'd least expect it.
-And it doesn't actually matter. Your immune system can handle it, whatever it is. If you're seriously germophobic, maybe don't go outside, but if you're someone who has a dog, someone who has used the facilities at Penn Station and survived, etc., you will live and let live.

Oh, and the continued popularity of this genre suggests that there's a certain sort of person desperate for the approval of service-industry workers in particular, who will treat every encounter as if it's with the Soup Nazi, and who will spend time reading up on how to get on the good side of a bell-man. (Are there no bell-women? Is our only concession to PC acknowledging the bell-individual's adulthood?) This is different, I think, from basic manners, and from wanting to know what's an appropriate tip.