Years and years ago (we're talking when Hong Kong was still run by UK) I went back to work in Hong Kong from UK . One day I walked into a designer shop, might have been Christian Dior in the CBD as I had nothing to do after work. I know the shop assistant took one look at me and decided I wasn't worth her time as I was very young back then.
So I decided to have some fun and asked her a random question about the lipstick - in my perfect native English. As expected, I could see the immediate change in her face lighting up like a star with a big smile. I walked out of course without buying anything
hahaaha I could really try your trick! But like @ekavieka's mentioned above, it could be because some locals/domestic tourists don't treat the workers with respect which seems traumatizing them hence why, they kinda treat other locals that way where they tried to read the room first before deciding what to act on us. Still shitty from my perspective but it is what it is.