It sounds like you were very disappointed in the way they treated you--you were expecting to be treated as if you were a customer and you were not. It also sounds like they are very protective of their most expensive pianos, for which I would not blame them at all. Whenever a piano is played, it inevitably gains marks of wear-and-tear which reduce its potential value to a purchaser. Remember that Faziolis are among the most costly of pianos. I wonder what kind of job you were applying for. Sales? In fairness, an applicant for a sales job is not likely to be treated like a customer, anywhere, but will also be expected to present himself or herself impeccably and, essentially, to show the utmost respect for, and compliance, with the wishes of, anyone he or she has to deal with.It sounds to me like you had your sense of your role confused. The piano shop you visited might well be a very good one which treats its customers extremely well. The way it treats its potential employees might be designed to be a real test of attitude towards frustration, of patience, of self-effacement and so on. The cost to a piano shop of hiring an arrogant employee might be very high.You might well telephone the owner or manager and explore these ideas openly. Apologize if it seems appropriate. If you do so, I would not be surprised if they asked you back to play for them and explore how you might fit into their workforce. Employers ususally like to hire employees who learn quickly; they also know that all their new employees are going to make mistakes.
...The very worst thing you can do is to play better than your potential customer...