What is wrong with Social equality?

Social equality is an idea that everyone is to be  treated equally ,but can it be obtained ? I do not believe that it can ,because of the diversity of race,language, creed,and other variables, that make us human. I am of the opinion ,that as long as we can distinguish differences in others in contrast to ourselves ,that there will always be preferences or prejudices .(for example) If you had to choose between spending time with a friend and a complete stranger ,who would you pick? Most people would pick the friend ,but it doesn't matter who was picked because the act of preferring one over the other goes against "social equality", doesn't it? Even if you had to choose between two strangers ,you would  decide based on  the qualities that appealed to your senses and prefer one over the other.In order to put an end to preferences and prejudices ,and make all equal , we would all have to become one race; which, biologically speaking, is impossible, we would have to do away with families,we would all have to speak a common language, like Esperanto,we would all have to be of the same religion or have no religion, and we would all have to look, dress , think ,and act alike in order to make this possible. Is this how you would want to live in order to achieve social equality?