Originally Posted by
seavisionburma
The big no-no is to wear shorts in government buildings, immigration offices and the like - always dress respectfully (minimum trousers, no sleeveless shirts/singlets)
I'd add two things to that. One, shorts may be inappropriate when visiting certain temples, shrines, palaces, etc. Two, I'd argue that it's especially (Western) women who might need to dress differently than they would at home when the thermometer hit 30 degrees centigrade (~85 degrees Fahrenheit).