Frustrated performers

Every now and again I, along with virtually every other performer, will be criticised by a venue owner or event organiser who thinks they know better than us what our show should be.
I recently did an adult cabaret show where I was kept waiting an unprecedented hour and a half past my contracted onstage time. Having given my all to a largely uninterested, drunken audience, I left, disillusioned because my show had not been as well received as usual.
Imagine my incredulity when, the following day, my Agent contacted me and said he had had a catalogue of faults passed to him by the Bar Manager of the venue. He forwarded the email to me and, over the phone, we went through every point that had been brought up. Each and every one was either blatantly untrue or was complaining that I had not provided something for which I was never contracted to do (i.e. sing live and dance!)
At first I was at a loss to understand where this litany of alleged shortcomings had come from. Then a bolt of realisation hit me. In a conversation on my arrival the Bar Manager had confided to me that he was a failed/retired club singer. It all fell into place. There is nothing so bitter and venomous as a failed performer who misses the spotlight.
I thought back to another couple of instances when these sort of complaints had filtered through to me and in each case they had come from ex-performers.
Speaking to other acts I have heard similar stories of interference and bitterness. A friend of mine, a drag act with many years' experience, was resident in a pub and the manager pressured him constantly to modify his act. It turned out he was a wannabee drag act.
I have been doing my act for many years and am very aware of my capabilities and failings on stage. There is no point in my trying to be what I am not.