I expect the dentist was irritated by Zach's refusal to face reality.
I'd bet on a combination of that and his refusal to take his oral and dental health seriously. He sounds like the kind of guy who expects the dentist to "fix" his mouth (at little to no cost) and doesn't believe or understand that he still needs to brush his (remaining) teeth and floss regularly.
I also wonder if the "way too expensive" procedures and exams he's putting off aren't to do with getting dentures? With as few intact teeth as he has, I would imagine that his dentist would at least want to have a conversation with him about the idea of getting dentures. That would fuck with Zach's idea of himself as eternally in his early 20s, though, so he definitely wouldn't go for it even if it was totally free. I guess it could be other stuff like root canals, though, which can be very expensive (think ~$1k each).
A pro-tip for Zach: If the dentist is recommending specific procedures and has them noted in your file, and you're paying out of pocket, you can ask at the front desk for an estimate of costs. Lots of people don't have dental insurance or have terrible dental insurance and need to know how much things cost ahead of time, and most dentist's offices will be happy to help. You just have to ask the
office staff, because the dentist isn't gonna know shit about costs and insurance.
Honestly, I don't even disagree that dental health care is
wildly overpriced and underinsured considering how important it is, but the system is the way it is and the #revolution isn't coming anytime soon, so you have to man up (or, if you're not Zach, perhaps woman up) and deal with it the way that it is. Go get a part time job to pay for this shit, Zach, nobody is stopping you but yourself. It's not like you need to pay rent ffs.