What the hell is going on with shops?

I also love the argument about paying for all the cost of doing business stuff. What gets me there is that is all charged to the customer and then written off come tax time. Since I as the customer was the one paying for that stuff as pointed out above, shouldn't I get the tax writeoff? I don't know what the book says overall, just from the few things I have ever brought in or had done under warranty. The hours listed were always silly high for somebody actively engaged in the job with all the proper tools. I'd love to hear some specific times of what the book says for common things people here have done themselves so we could judge for ourselves your argument you get screwed with those times.
I do complain about the doctor rates as well. Last time in I timed the actual doctor time and then compared to the billed rates and shamed them on social media. Lots of people responded with "why do you care you have good insurance?" Exactly one reason our healthcare is getting so expensive. That, over use, and lawyers.