Shaun & Rebecca, Agents A secret commander is the idea that your actual commander is a front for a much more important legend in the 99 of your deck

On newer cards, the front label uses a black border as well as the following: A holographic version of the CGC logo on the top left The cards official name among collectors on the left, along with any other varieta details underneath (for example, what promo series it falls under) The cards grade and score on the right A bar code and certification number on the bottom left, which can be used to research the card in CGCs Cert Verification database On the back, you should be able to see the following: A holographic security label with the CGC logo and verification website ( CGCcards.com/verify ) on the left Next to that, a QR code also that leads to the Cert Verification database to help identify the card The score again on the right These markers of authenticity will help you verify the authenticity of a CGC-graded card but make sure you also look up the card in the CGC database to determine more about when it was originally graded, too!
Take Anafenza, the Foremost for example
As you said it just depends on the person behind the counter
If you can look at one card, say, a Water-type card, and see that it's weak to Lightning-types, and you understand that the Lightning-type Pokemon that attacks your Water card will do twice as much damage
maybe you find yourself wanting more copies of Dogmatika Fleurdelis, the Knighted, or prefer Evenly Matched to Book of Eclipse