I don't use self-checkout for one reason only: if I am doing the work, why am I paying the same price. It's just another scheme by the business people to get them more money.

There are far better ways of queuing, and they can always hire more people to deal with the demand. But no, they figured out hiring fewer people makes it inconvenient for many, which is an incentive to use self checkout, which gives them even more money on top of already high margins.

Same thing with gas stations. No thanks. I'll happily leave a tip to people providing the service, but it's a matter of principle. You don't go to a restaurant and rummage through their refrigerator to get the meal, nor should you serve yourself anywhere else.