I saw this thread and wanted to pop in and say how wonderful you all are! I am really proud of you guys for openly and kindly talking about the things that make us all unique. I haven't travelled as much as others, but I have been to Europe and Central and South America. What I have discovered is that we are all different and are all the same. I just depends on what level you are talking about.
On the important stuff, almost all humans are remarkably the same. In fact, the differences at this level are more individual than societal. For the most part, we all want: to love and be loved, to have our basic needs met, to find happiness, to find work that is enjoyable, to love our families and cherish our children, and to grow old in peace. These are common to all societies, but not all individuals. How the society builds itself around meeting these big needs is what makes us all different. It is also, often, what causes war and conflict.
Conflict arises first if there are not enough resources to meet the needs. However, most major wars have been fought over lesser issues, such as religious beliefs, political systems, language differences, and cultural nuances. These things are all important, but they are based on cultural differences rather than human ones. I have always found it interesting that we fight over the little things more often than the big ones. Such is the human race, I guess.