Learning to cut meat in a supermarket is like reading a book starting in the middle. You never get the whole story.
Half the process is already complete by the time the meat reaches the supermarket. Why? Because the meat arrives at the store in large packages of pre-cut primal cuts, ready for further breaking down into retail cuts.
All an apprentice meat cutter learns in a supermarket is how to slice primal cuts (which are well labeled) into steaks or roasts. In other words: “Cut along this line and don’t ask why.”
He or she generally won’t know where the cuts come from on the animal, why certain cuts are tender or tough, which cuts are better suited for long, slow moisture cooking, and which for faster dry cooking.
You get the picture. THEY’RE NOT BUTCHERS.
So ask questions. If your supermarket’s meat people can’t answer your questions and give you that Duh? look, then be wary.
I don’t want to give you the impression that I’m against supermarkets. I’m not; they’re an efficient way to shop and have made life a lot easier for working people. But I do hold a tiny grudge against those which advertise their “butcher department” when I know d*mn well that there’s no such thing behind those white doors.