You cannot tell the difference between "Authentic" Mexican & Italian food vs. their generic versions.
I'm sorry.
You can tell the difference between authentic Chinese food vs. generic
You can tell the difference between authentic Indian food vs. generic
You can tell the difference between authentic Cajun food vs. generic
You can tell the difference between authentic Soul food vs. generic
You can tell the difference between authentic Caribbean food vs. generic
African, Southern, and the list goes on.
When it comes to Italian food, I've had "authentic" Italian and that shiit always tastes just like the bullshyt they serve at Olive Garden. It's hard to do anything different when 90% of your dishes is just Meat, Sauce, Cheese, & Pasta. You never hear people say, "Oh there's this Italian spot..." Nope. It's always just whatever Italian spot you see, will do.
Same kinda goes for Mexican. Not as much as Italian though. I've had "authentic" Mexican from hole in the wall Mom & Pop spots and even in Mexico, and it's not much different than what you get at many generic Mexican restaurants. There is some difference, but not anything major. Again it's hard to really do anything different when 90% of the dishes use the same ingredients. Meat, Cheese, Peppers, Tortillas.