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

"In Phnom Penh, it is considered disrespectful to touch someone's head, as it is regarded as the highest point of the body and therefore sacred. Avoid using your feet to point at things or people, as feet are considered the lowest and dirtiest part of the body. When visiting temples or other religious sites, dress modestly, covering your shoulders and knees. It's also important to remove your shoes before entering someone's home or a temple. Public displays of affection are generally frowned upon, especially between men and women. It's also considered impolite to show anger or frustration in public, as maintaining face and harmony is highly valued in Cambodian culture. When eating, use your right hand as the left is considered unclean. Also, never leave your chopsticks sticking upright in a bowl of rice, as it is seen as a bad omen. Avoid discussing politics and the country's past, particularly the Khmer Rouge regime, as these topics can be sensitive. Lastly, always negotiate prices when shopping at markets, but do so respectfully and with a smile. It's part of the local culture and expected, but aggressive haggling is considered rude," remarked another expat in Phnom Penh, Cambodia.