insisting that someone leaves what they're doing to open a till for you is pretty entitled behaviour
no it isn't, when I've worked in customer service jobs you serve customers first and then go back to what you were doing. I know people argue on here that not all shop staff are trained to use the tills in which case they can say that to you, but usually they just ignore you in a calculated way.
I use the self-service tills because they are faster, but only if I don't have to queue. If I have to queue I go to a cashier. Self-serve is fine if it is convenient, but it's not convenient if I have to queue.
Agree that the Waitrose machines are great and the others are a pain with theiir unexpected item in bagging area, or not accepting vouchers or you find you have an age-restricted item.
But then Waitrose decide to put a 16 year old on the cigarette counter, so you go there with your bottle of wine to avoid hanging around for a supervisor - and then find you still have to hang around for a supervisor.
I do think the supermarkets could look at the shopper's experience a bit more, with a view to improving it. No staff under the age of 18 should be on counter selling age-restricted goods.