True; a 20-minute difference would definitely be enough to tip the scales in favor of self-service. But in the grocery stores in our area, there are almost alw

True; a 20-minute difference would definitely be enough to tip the scales in favor of self-service. But in the grocery stores in our area, there are almost always plenty of registers open and little waiting. So the time requirements being approximately equal, I'd rather pay a skilled cashier and bagger to do the work of speedily "ringing up" and bagging my groceries, while I stand there and chat with them. (As a teenager I had a summer job bagging groceries one year, so I can relate.)