Some professional travelers deeply research their destinations, mapping out the majority of their trip, reading up on local customs and quirks, and learning the local language/dialect.
We are not those travelers. We're opportunistic travelers, relying on our wits, adaptability, and random chance to create and enjoy our experiences as we travel the world.
Case in point - language. Specifically, accents. Anyone who assumes "Spanish is Spanish" hasn't considered the Texas farmer trying to get directions from the Jersey boy. Switch either with a cockney speaking barrow boy and watch the conversation go from halting to full-stop. We all talk funny.
I speak a little -- very little -- Spanish. As I said as an insensitive prick of a kid, I speak just enough Spanish to get my ass kicked in a kitchen. In recent years, I've worked on that (attitude as well as knowledge base) to add several words and phrases to my lexicon. Today, I can suss out the intent behind signs and notes, and headlines. I can say I'm sorry that my Spanish is poor, stumble through asking for directions or, explaining that Sheila's a vegetarian by way of example.
But all of my spoken Spanish, I've come to realize, isn't really Spanish. It's Mexican. And Mexican is very different from Galician Spanish. And Galician Spanish is very different from Republica Dominca Spanish. Which is probably different from... you get the picture.
Where I come from -- the ass-end of nowhere, or the plains states -- it's not uncommon to hear overly-Americanized bits of Spanish thrown in to everyday conversation. Blame it on TV and movies if you want. Amigo (Uh-MEE-Gho). Vámonos (ala Speedy Gonzales). Gracias (grassy ass). These aren't uttered to demonstrate prowess of another language or sensitivity to a different culture. Quite the opposite. Their mostly derogatory and filled with contempt. I'm not proud I've used those words in that context in my dumber years, but I'm trying to get better.
So when I got off the plane and was told "grassy ass" by locals, I was shocked! At first, I though they were screwing with me. When we were in the Dominican, the waitstaff at our resort encourage their idiot guests to say "mucho gusto" when the meal was good. Mucho is "much", and gusto is "taste," so no problem, right? Wrong. Mucho gusto is the equivalent of "nice to meet you". Well played. So yes, you should stop saying that after you eat a meal. Unless you're a cannibal.
In Galicia, the rolled Rs are softer, and the emphasis is placed on different syllables. So "grassy ass" is a perfectly fine way to say "thank you" over hear. That, or they're all screwing with me. I can't rule that out.