Bhutanese people have a deep, traditional reverence for the Royal Family, & a visitor should be careful to show respect for the King, & other members of the Royal Family.
Visitors should dress neatly in all religious shrines. They should never go topless, or in shorts, hot pants or other unsuitable attire. It is acceptable to wear shoes when walking around the compound of a Buddhist temple, but not inside the temple.
All statues & paintings, large or small, ruined or not, are regarded as a sacred. Never climb onto one to take a photograph or do anything which might indicate a lack of respect. Pointing with your finger at statues, paintings or people is considered rude. If you must, point with your right arm, your palm open & facing upwards & your thumb folded inside.
Because tourism is new & not very big, it has not yet made any negative impact on the people. People get excited to pose for pictures, especially when asked by a tourist. But if you want to get close up shots of people, you should ask first. No photography is allowed inside temples & Dzong.
Public displays of affection between men & women are frowned upon.