Often the core is the feeling of being disrespected. There are people who actually lack the ability to genuinely respect others. You did good sharing what frustrates you and contributes to your anxiety. Once you identify certain patterns the next step is to work on changing the role you play in the scenario. I gave you an example with that one challenge you pointed out.

One thing I learned from the many years of dealing with different customers is often people have little to no knowledge about what I do and what it entails. I gradually came up with rules I would communicate to customers. People never ceased to amaze me how little they knew. What I considered basic and common sense was often simply unknown to many.

With that said, often people can be genuinely clueless when it comes to showing personal respect and genuine kindness.