I don't understand your attitude. What else are you doing while standing there at checkout? I marvel at the folks who stand there doing nothing while the cashier rings everything up, then stand there doing nothing while the cashier bags everything up. If I'm at a staffed checkout I will bag things up myself and be out the door a couple minutes faster. Sure I am "doing work" but it ends up costing me less time and I am helping keep their margins which lowers cost for everyone. I do self checkout when available and am quite efficient at that. I help keep prices down, spend less time at the store and see it as a win-win.
The unfacts, did we have them, are too imprecisely few to warrant our certitude.