If a group of people have always lived in the dark and are told a light is going to be turned on so that they will all be able to see each other, they may very well object, believing that since a single lamp will be shining the same light on everyone, they will all look identical to each other. But, of course, we know that the light would bring out their individual distinctiveness.
Union with a single Christ is like that. You are given back you true self. You become the you that you were meant to be.
(Analogy originally from C.S. Lewis)