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

"It is important to be mindful of local customs and traditions when visiting Exeter. It is polite to greet people with a smile and a friendly hello. It is also important to be respectful of the local culture and to dress appropriately. Avoid making negative comments about the local culture or customs, and be aware of any religious or cultural holidays that may be celebrated in the area. Additionally, it is important to be mindful of the local language and to avoid using slang or colloquialisms that may be unfamiliar to the locals," said another expat in Exeter, England.