It is hard to know which of our values is most positive given that our values tend to have both positive and negative sides. Let us look at two important American values that have positive sides.
First, there is the value of individualism. We believe in individual rights and liberties. This gives us a society in which people are free to be themselves and to be what they want to be. They have the greatest possible freedom to pursue their talents. This is very positive, but it also leads to a society that can be somewhat cruel to those who fall behind in individualistic competition.
Second, there is the value of patriotism and the sense that our country is special. This is positive in that it makes us proud of ourselves and it makes us try to help other countries to progress and be like us. But this can be negative too when it makes us arrogant and blind to the idea that other countries may have their own ways that they value.