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

"It is important to be mindful of cultural differences when visiting Lisbon. It is considered rude to be late for appointments or social engagements, so it is important to be punctual. It is also important to dress modestly, as revealing clothing is considered inappropriate. Additionally, it is important to be respectful of religious sites and to avoid taking photographs without permission. It is also important to be aware of the local customs and to avoid making negative comments about the country or its people. Finally, it is important to be aware of the local language and to avoid speaking English in public unless it is necessary," remarked another expat who made the move to Lisbon, Portugal.