One of the topics I was always fascinated by in high school was ethnocentrism. In short, ethnocentrism is judging other cultures by the values of your own culture. The stereotypical, ugly example I frequently come up with is people in the US criticizing migrant workers for not having well-developed English speaking skills (or American, as some of the more delightful ones put it).
A less toxic example is that of WWII. For the US, WWII didn’t really ‘start’ until the attack on Pearl Harbor, even though in Europe it’s broadly considered to have started with the invasion of Poland (and to a lesser extent the Winter War between Finland and the USSR).
That said, there aren’t always weighty issues that crop up in this self-centered approach. I had a funny one happen to me when I was delivering papers as a carrier in North Carolina.