I look at the symbolism found throughout the series to create my own interpretation of the ending. when i first saw the series, i must have been around 12 or 13, and at that time my mind wasn't really able to grasp anything behind the huge mecha's and the action. but now that im older, from what I received from the series was that of lonliness, each indivdual main character is alone from the start, then in the middle they have eachother, but at the end they all fall alone again. through an emotion spiral and a psycological journey, each of the characters must find themselves, and in order to do this they must do it alone. example is that Shinji, being very weak minded, needs a crutch throughout the series, his crutch being EVA, but at the end, he's left to deal with his many trials and tribulations alone. that's what i received from it.