I’m surprised that, in this day and age, anyone would use the “do you know who I am?” retort.
Many of the clients I worked with (homeless and vulnerably housed people) were very rude initially, but I understood it was usually born of frustration and intolerable circumstances and tried to model patience and good humour.
However, one homeless client, publicly schooled and from an extremely wealthy background, was intentionally rude and entitled on countless occasions. One time he was berating me publicly and I gave him the worst dressing down I suspect he’s had since he was in short trousers. Although his attitude generally didn’t change much he became much more circumspect with me - and other clients who witnessed or heard about the exchange became less intimidated by the man’s bullying ways.