Here's the thing about culture: it makes a HUGE difference in any sort of human to human interaction.
I never really thought about it much until we started the different training programs for our two years in Scotland. MTW (Mission to the World; they coordinated our training and manage our funds) did a great job of helping us see the challenges that would come with being immersed in a totally different culture that we previously knew next to nothing about.
It seems that many conflicts that occur when more than one culture is represented probably stem from failing to understand cultural differences. From the perspective of being immersed in a foreign culture, I can look back on interactions I've had with people from other cultures and see how much I didn't understand about who they are and where they're coming from as a result of our differing cultures.
So many of our personality traits are deeply rooted in aspects of our lives in which we had no choice: birth order, number of siblings we have, what country we grew up in, what area of that country we grew up in, the culture and experiences that our parents had, etc.
I was having a conversation with some Scottish friends the other day about stereotypical characteristics of various cultures. One of those characteristics I thought was universally known (and 99.9% true) they were completely unaware of.
How many of these characteristics are out there that we don't know about, but are assumed to be universally understood? How many times have we totally misunderstood a friend because we failed to take into account their culture, even if it is the culture of the neighboring state or county? And the question I ask myself all the time, "How many times a day do Scottish people laugh their faces off after I walk away because I've said something that sounds so ridiculous to them?"
Sometimes practices of other cultures are just straight up bizarre, but they're probably thinking the same thing about you.