Being close to another person in Mexico City is a cultural
norm. In an urban area as densely populated as this city, people are
used to being crammed together on buses and subway cars. If there is
even the slightest room for someone to sit down next to you in a
coffee shop, then someone will sit in that space - regardless of
whether or not they will have to physically touch your person. Men
especially have no qualms of showing physical affection by hugging
other males simply as a form of greeting. Awareness of sociocultural differences will help you avoid social conflict
and build solidarity with members of the target language culture.
Pragmatics is the study of how language is used in communication. As a learner of a foreign language, what you are learning is actually interlanguage (IL) pragmatics because you already have pragmatic knowledge of your first language while you acquire pragmatic knowledge in your second language.