M3 Dust - you are probably a good guy to detail for, and a good person in general. However, the reality is that the majority of customers that call and specify certain products (beyond just a wax or sealant), or a certain process, they are more often than not a problem.
For a lot of us, we at least have enough work to stay busy (and many are booked up for weeks), and it isn't worth it to us to possibly get invlved with a customer that we could provide the best detailing job ever, and the customer still not be happy - especially when there are warning signs. In this case, many of us on this site would have not performed the detail for you, and we would have missed meeting you, and making money off your detail. However, that's where the risk / reward analysis comes in. With this being such a word of mouth business, many of us are willing to pass the reward in order to avoid the risk of a customer badmouthing us because we didn't use the exact produts / techniques they wanted, so the car wasn't as good as it could be.
Sure, you can potentially have issues with any customer, but in this case, there were signs.
Just my "absolute worst case $.02"