"Sheen-bro" [English translation: "Machine is broken"] is the standard Ebonic excuse for any difficult or mildly complicated task. Just try to order ice cream at any "diverse" McDonald's and you'll have 80% odds that the machine will be "broken" or otherwise out of order. On the other hand, go to any Chick-fil-A for the world's best milkshake -- and you'll get it. What's the difference? Selective hiring and a corporate culture that instills, reinforces and rewards a solid work ethic.
So true. Even if you must hire from a low to lower-middle class neighborhood, you are likely to see different gradations of personality, skill and positive attitude.
Those with the right personality or attitude can be taught skills to some workable level. Some of these single mothers are serious about working, and very motivated to earn their money.
A great deal depends on selecting the right Manager for such places. The Manager often sets the tone and is an authority or parental figure. If the Manager skates, openly lies about punching in, curses our co-workers in public, leaves stuff undone for the next shift, or is rude to certain races of customers, that will immediately get noticed and imitated.