Worked in retail for a supermarket for 8-9 years then 14 years customer service. I can tell which people have not worked in retail or customer service.
I doubt that they would be rude, abusive towards staff if they have worked in the sector. As I have asked these people the question have you worked in retail both as a customer and when working. Everyone I asked said no. I said that question in a neutral tone.
I believe that everyone needs to work in retail the busiest time of the year- ie December for at least a month. If this doesn’t change their attitude towards the staff, then nothing will as nasty people.
Even on 22/23 December one year I had customers asking for more tills to be opened. ALL of the tills were open!!