Before I get started, don't anyone get offended here. Don't shoot the messenger! I'm just reporting the facts, folks, just the facts. I know I speak with a sailor's tongue, but that is basically confined to English. When I speak Spanish I don't use that many expletives. However when I learn any new language, one of the first things I want to do is recognize the "bad" words. When I lived alone in Akumal, Quintana Roo, in the 1980's, I needed to know the Mayan cuss words. If someone offended me I wanted to be able to recognize it and defend myself. I approached Hawaii, Samoa, Tonga, Fiji, Australia, Bali and anywhere else I've been the same way.
One of the terms I have heard often here is "maricón". It is the Spanish equivalent of a derogatory term for gay, like "queer" perhaps. It isn't a term I use at all, but I do hear it a lot. The local guys use it liberally in their salutatory banter. Therefore it sticks forefront in mind as an important idiomasyncracy.
I often find myself walking along a seawall, or malecón. I hear the word malecón and images of La Paz in the 70's, Cabo San Lucas or Cozumel in the 80's, and Progreso or Celestún in the 2000's are conjured up in my mind. I think of a romantic stroll along the seawall in any sea town, Mexico.....but the beautiful thought often gets interrupted with the sound of the word marícón flying through my head. If I see a male prostitute on the seawall, I want to break into song. Watch out for this idiomasyncracy, you could get yourself into trouble.