OK. so some things are different in the area of what offends and what doesn't. For newbies can we dredge up what we've learnt along the way. I'll start.
Don't point with your finger (at a person) use your thumb. (unless what you really mean to say could be expressed in English with one finger only)
When beckoning use all fingers, pointed down, not up, Don't ask me, maybe more of the same)
Left hand is considered unclean, pass things with the right and if you really want to go that far and you're eating with your hands, use the right one (that is the one that's not left, not the one that is correct, although the right one is also correct)
Now, this is a good one, Your knickers really shouldn't be hanging above the room cleaners head when he is cleaning the bath/shower.
Then there is the,don't touch peoples' heads.
nor put your feet up on the table or opposite chair so that your soles are pointing at another person.
try not to be "loud"
nor to expect over effusive thanks for a gift which would make the recipient appear greedy.
Of course they make all the allowances in the world for us uncivilised foreigners, so don't lose any sleep over any of the above.
Happy holidays. Yes you, I'm talking to you there. Yes I am pointing at you and not thumbing a lift.