Here, it is considered good manners to wait for invitations. That applies to most everything of daily life.
When first I arrived, it would have been very disrespectful of me if I had helped myself to whatever I wanted to eat or drink right after the family had shown me where it was. This is because, here, I am a guest. A guest does not serve himself until he is part of the family. A guest is served. As I become more accostomed to my host family, and they to me, I begin to aquire “family rights” as it were. I offer to help with dinner, or with washing the dishes now. Usually the señora accepts my help. Sometimes, she insists she’s fine, and tells me to sit down and watch the television while she does the dishes, or whatever. My general rule-of-thumb is that if it’s a meal for more than 3 people, I always offer to help with anything and everything. Otherwise, the doña thanks me, but does the work herself.
Another thing I’ve noticed that I’ve found interesting is this: gratitude.
In Spanish, when someone wants to say “thank you”, they say “gracias” or “muchas gracias” (much thanks). Generally, the rough translation of “you’re welcome” is “de nada” or “it was nothing“. Here in Costa Rica, the more common form I hear for “you’re welcome” is the phrase, “con gusto“, or “with gusto/pleasure“. It means something similar, but not the same. To me, “de nada” more or less takes the gratitude and shrugs it off: it was nothing. By contrast, the phrase “con gusto” more or less expresses the speaker’s attitude toward serving. The Ticos are very much a serving people.
Something to think about, I guess!