Cultural differences can be somewhat of a shock for people who are not easily acclimated to change of country or region. It becomes even more difficult when you are not just a tourist but have to actually live in a place you know little about.
It's always a good idea to prepare for this by learning as much as possible before hand but in my experience sometimes there is no getting around the fact that as a foreigner you are bound to make a mistake or a two. I have done it a few times but thankfully I had people around me for damage control.
Not to be rude or anything but as long as you stick to major points, I do think that sometimes people need chill out :-)
I think you are right, as long as you make an effort to try and at least respect the country that you visit, some faux pas tend to be easily forgiven.
Yes, most people usually understand and give a certain amount of leeway in these matters to the foreigners. Given of course that they know that it was unintentional.