There are many pitfalls for the unwary in a cross-cultural context. Here are some bloopers I, or those with me, have made:
India: placing my Bible on the floor.
Mozambique: beckoning someone to come with my palm facing up, rather than down.
Muslim nation: offering (as a woman) to shake hands with a man when introduced.
India: a young woman making eye contact with a man.
Russia: wearing outdoor shoes inside the house.
Mongolia: not eating everything my plate (or offering it to someone else to finish).
These may just be superficial things, and thankfully I have always been in a context where, as far as I know, the local people have excused my blunders, but they speak volumes. It is so easy to unwittingly offend. Things that we take for granted in a Western context may be a sign of disrespect that is totally unacceptable in another country.
That's a small part of the reason that missionaries need cross-cultural training.