There are many, many examples of such differences in meanings that make life experience so unique for all the human groups around the world. For example, English has tenses built into our verb forms, so we automatically think in terms of time (being punctual, time is money, make the time, etc.).
The assumptions we make about others' experience can involve false negative judgments, reflected in the common definition of ethnocentrism. Assumptions can also reflect false positive attitudes about others' ways. False positive assumptions are just as misleading as false negative assumptions.
Ethnocentrism leads to misunderstanding others. We falsely distort what is meaningful and functional to other peoples through our own tinted glasses. We see their ways in terms of our life experience, not their context. We do not understand that their ways have their own meanings and functions in life, just as our ways have for us. We aren't aware that we can develop more valid understandings about how they experience life.
A lack of understanding can also inhibit constructive resolutions when we face conflicts between social groups. Ethnocentrism is also evident in international relations, creating conflicts and inhibiting resolution of conflicts. If we don't win the conflict, will we lose? An ultimate case of such misunderstandings is warfare, where many people are killed, maimed for life, have their families, subsistence, health, and way of life disrupted, sometimes forever.
Addressing ethnocentrism is not a matter of trying not to be ethnocentric. This is an impossible task, since we will never experience every life situation of everyone around the world. The scientific process helps us have a clearer view of what we do understand in the context of what we do not understand. Ethnocentrism is a bias that keeps us from such understandings of other people's life experience, but it is possible to recognize this bias and control for it so that we can go on to develop more valid and balanced understandings. This calls for us to develop our learning skills. Many of us know people who have moved to other societies and have learned to become functional in their new social settings, evidence that it is possible to develop more grounded understandings. Anthropologists have worked on systematically developing these skills for well over a century.
The first step in developing more balanced understandings is to recognize that we do not understand, that we are falsely assuming something that is not the case and is out of context. One of the most effective means for recognizing that ethnocentrism is inhibiting our understandings is to watch for reactions. Reactions tell us that we are assuming something and that our assumptions are not working.
We can always observe our own reactions. For example, we may feel Indians are unfriendly because they are often nonexpressive in social situations, but recognizing our reaction can provide an opportunity to better understand their values on self-control which can be adaptive when a small family group has to be self-sufficient in a winter camp far from others' help.
We can also observe their reactions. Again, their reactions may be both positive and negative. For example, if an Indian shows gratification when we give him a gift, recognizing his reaction can provide an opportunity to better understand adaptive their values on economic leveling rather than assuming that our generosity has been duly recognized.
Why do we think people should be "friendly"? Once we realize that we are not understanding, we are now in a better position to seek more valid and balanced understandings. If we appreciate that their life experience can be as valid for them as ours is for us, acknowledge that we may be misunderstanding, and ask them to help us understand, most people are more than willing to help us understand better.
Perhaps no one can ever have complete understanding of another people, without fully experiencing everything they experience. However, this does not mean we cannot develop a functional understanding, to interact successfully with others. Like other life skills, practice at every opportunity helps us develop our abilities to catch ourselves being ethnocentric and asking good questions to better understand others' cultural behavior.