The word "Autism" and "ego-centered" are frequently used in the same sentence. To many non-professionals this may be easily misunderstood to mean "egotistical" or selfish. Of course this is not the case. With human nature the way it is, everyone is ego-centered to some extent. Some people just have the skills to hide it better than others.
Here are some examples: Many people in the rural Northeastern US would not argue that Boston is a big city with over 6 million people in the metropolitan area. However on a worldwide scale it doesn't even make the top 40 metro areas no matter how you measure them. To someone from Tokyo or Delhi it is a small city.
A Canadian moving to Washington DC may describe their new home as having a mild climate with an average January low of 29F- not bad. However someone moving to the same place from Puerto Rico(where the temperature has never been recorded below 39F) may think of DC as a cold climate. Both are right.
On a cozy night before Christmas in Montreal to state that it is a cold winters night seems like a no-brainer. After all Christmas is a Winter holiday... or is it? In Alice Sprigs, Australia it may be a hot, sunny Summer afternoon. In coastal Australia Christmas means a trip to the beach and maybe some sunbathing. As for much of Pakistan, one of the largest countries in the world, December 25 might be just another day.
What about the Far East? Think Japan, China, South and North Korea. What makes them Far East. They are pretty far east on the map and Orient means East. East of what? The world isn't flat. To Hawaii, Japan is Northwest. Does this make Western Europe the center of the world?
What about that "rude" foreigner who thinks we're rude. Both parties may know the basics of each other's native language but not the dynamics. In English a statement that would normally seem curt and direct becomes polite based on how we raise or lower our tone of voice while saying it. In a different language the same tone of voice may have a different meaning. This is stuff they tend to not teach in basic level language classes.
Not all generalizations are malicious as long as they are accepted as generalizations and not absolutes. To say Russia has cold winters and one should be prepared when traveling there sounds reasonable. Most of this huge country does get pretty cold and some parts get colder than the North Pole. The Black Sea coast on the other hand has Winters mild enough for there to be a good amount of palm trees. While sunny Spain, Argentina, and Chile have ski resorts that may get more snow than anywhere in England. My point it not all generalizations are bad as long as one respects possible exceptions and contradictions to the rule and doesn't confuse the general with the specific. Not to say there are no absolutes, there are, but many of the things people get into pointless heated arguments about are only relative and both sides are both right and wrong.
While most Anthropology and cultural studies examine the differences between "us" and some far away exotic "others", it's easy to forget that there are cultural differences between individuals and even households in the same neighborhood. 2 kids may have both have been brought up to be thoughtful, respectful and have good manners, but may get some stern looks by their friends parents when visiting another person's house. What one family emphasizes as good manners may be different for another family. While many households expect us to take off our shoes at the door, people in another household may be perplexed as to why an acquaintance or even a repair person just took their shoes off when the came in. To some it may seem too familiar but to others its only common courtesy.