1. Ethnocentrism is the act of judging another culture based on the standards that we have in our culture.
At appropriate level, we could argue that ethnocentrism actually bring a sense of pride towards our own culture which lead to positive functioning of American Culture that perceived as desirable by others.
2. Too much ethnocentrism could be seen through the effort that people of our own culture made to diminish or eliminate others people culture.
One example where you can see this through the constant insult that people made through social media towards another culture.
3. Excessive ethnocentrism will create a strain in the relationship between one ethnic and another.
In a nation with diversified culture such as united states, this would create a problem where constant clash/conflicts between ethnic groups that lead to violence may happen