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

"It is important to be mindful of cultural norms when visiting Luanda. It is considered impolite to show up late to social gatherings, so it is important to arrive on time. It is also important to dress modestly and to avoid wearing revealing clothing. Additionally, it is important to be respectful of local customs and traditions, and to avoid making negative comments about them. It is also important to be aware of the local language and to avoid speaking English in public, as this can be seen as disrespectful. Finally, it is important to be aware of the local customs regarding physical contact, and to avoid touching people without their permission," mentioned another expat when asked about moving to Luanda, Angola.