This.....
No-one deserves abuse or aggressive behaviour in whatever role they are in, and whatever background they are from.
If you're acting like "normal polite customers" are the enemy and punching down on them then of course every shift will be a battle. Becomes a vicious cycle.
You see the difference in some stores where the whole team has a positive and helpful attitude, the customers are nice back and nice people come back....So you have good interactions to get you through the day.
I've done my time in physical customer service work, and enjoyed some of it for sure.
Unfortunately you do see some people with a "too cool for school attitude" where staff saw themselves as above the customers. Just show some humility and be polite to people and don't judge or try to get one over them!
There's no need to get into an argument over a reduced price bun. The store isn't going to close over 35p. It's not like you're debating the existence of evolution. You don't even need to be super-extroverted, do the shift on emotional auto-pilot and look forward to finish time.
I agree working in customer service, or a posh shop, isn't like in some romcom novel where a rich alpha male customer sees your sparkling eyes and decides to marry you.
But like @suki1964 says you can still be civil and polite and take pride in helping people.
It's too common to see staff giving appalling service to non-white people, solo women, elderly people, anyone perceived as vulnerable/early dementia just for the sake of it. Then the profits drop and the staff are under more pressure.
As a customer, I'm not white and I'd say I'm just about the perfect customer (techie so super-quick on the self-scan, polite, don't bargain hunt. I consider myself civic minded and would probably intervene if I saw someone being rude to a staff member).
but to be honest I'm just fed up with being treated like shit or an inconvenience in many places - you frequently see some frustrated customer service person deliberately lash out at me due as they don't think its right that they are in a "service" role for someone with my skin colour.
(and the great pity - I'm probably the last person in the world who would be looking down on a shop assistant, or anyone).
I now vote with my feet and mainly use online not physical... I don't overthink this and I'm lucky to have the budget, but I often even TIP the polite gentlemen who deliver my food (and if it's a family or group order I'm bossy so we ALL tip). I also run down the driveway so they save time.