Why the grammar is not enough
You can build a correct Portuguese sentence and still say the wrong thing. Which form of address you pick, how directly you state a preference, whether you use a title, all of that is decided by things no grammar book covers.
Five threads run through most of it: a particular kind of longing, a persistent formality, several centuries at sea, the café, and a country that is small enough to walk across and still argues about its own north and south.
1. Saudade
The word everyone calls untranslatable, which is nearly true. Not homesickness, though it can be that. Closer to a settled ache for something absent, and specifically one that you would not necessarily want to be rid of.
It matters linguistically because it sets a register. Portuguese leans indirect and reflective where English would be brisk, and a good deal of fado and literature assumes you already understand why the sad thing is also the beautiful one.
2. Formality that did not go away
Brazil flattened its forms of address. Portugal did not. Social distance is still marked, still noticed, and still capable of causing offence when you get it wrong.
Você is the trap. It sounds neutral and lands cold, sometimes worse. What people actually do is drop the pronoun and let the third-person verb carry it, or use the title: Doutor, Engenheiro, Senhora Dona. In fiction the titles do a lot of quiet work, and a character who stops using one has told you something the narration never will.