What cultural faux pas should I try to avoid making in The Algarve?

"It is important to be mindful of cultural differences when visiting The Algarve. It is important to be respectful of local customs and traditions, and to dress appropriately. Avoid making negative comments about the country or its people, and be aware that public displays of affection are generally frowned upon. Additionally, it is important to be aware of the local religious customs, and to be respectful of religious sites and ceremonies. Finally, it is important to be aware of the local language, and to make an effort to learn some basic Portuguese phrases," said another expat in The Algarve, Portugal.