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

"It is important to be mindful of cultural norms when visiting Phan Thiet. It is important to dress modestly and to avoid public displays of affection. It is also important to be respectful of local customs and traditions, such as removing your shoes when entering someone's home. Additionally, it is important to be aware of the local language and to avoid speaking loudly or using offensive language. Finally, it is important to be respectful of religious sites and to avoid taking photographs without permission," remarked another expat in Phan Thiet, Vietnam.