As Dickens writes of the French Revolution in A Tale of Two Cities:
It was the best of times, it was the worst of times ... it was the season of light, it was the season of darkness, it was the spring of hope, it was the winter of despair.
The same could be said of the 1950s.
First, there were, metaphorically speaking, two "cities:" that of white America and that of black America. For whites, it was decade of great prosperity and peace: the Depression was over, World War II was over, the economy was strong, unions were strong, the United States was a respected superpower. Many whites saw their living standards rise as they moved from cities to suburbs and bought cars and consumer goods.
Black America, however, did not participate fully in this prosperity, especially in the South. This was still a decade of segregation: segregated beaches, bathrooms, lunch counters, and water fountains. Voting rights were denied to blacks in many Southern states. People could legally refuse to sell a home to a black person. Discrimination was open and widespread. Blacks, despite the Civil Rights movement, were still a very disadvantaged group.
While the 1950s was a season of light--the US built a sophisticated highway system and embarked on the space program--it was also a period of darkness with McCarthyism and "red scares" for a time dominating the political landscape.
It was spring of hope as people believed, perhaps as they never have since, in the power of technology to unequivocally improve human life. It was also a winter of despair as people for the first time, with the immensely powerful hydrogen bomb, faced the specter of nuclear annihilation.
Such a decade of paradox and contradiction came to a head in the decade that followed.