I feel like TVD lacks logic completely, especially this season. It is hard to understand why even they give their characters a certain build up only to completely change them later. Elena wasn't supposed to be like Katherine in terms of personality and that's what both brothers loved about her, now she is the new Katherine and why would they still love her? More than that, Damon even admired the fact that she acted like Katherine in some episode which makes such a little sense. Literally nothing fits the characters that we knew, now they are like completely different characters and the story barely makes any sense.