I find self-checkout pretty pleasant to use if implemented correctly. A positive experience was an Ikea store where you just scan everything and walk out with occasional checks by a security guard. Or even better at Decathlon where you don't even need to scan things - you put it in a special box, and the machine recognises them itself. On the opposite side of the spectrum there are machines at supermarkets that try to be smart in a wrong way - complaining about what bags you are using, where you put them etc. About third of the times I decide to use those I end up having to call a human worker.