Why do some kids hate their step parents?

I consider it a blessing that my daughters really love my husband. We tried to integrate them into our relationship in all ways because we knew, as a stepdad, he could theoretically have a hard time. Fortunately, they have accepted him completely (including giving us the "green light" when we asked their opinion about us wanting to get married three years ago... we wanted them to feel part of all decisions that meant a serious change in the family). I think, as cool as step-parents can be, there are always kids who are going to put their defences up, right from the get-go. Their parents are divorced, they're perhaps really angry, hurt, struggling, depressed or all of these, rolled up in a ball. Kids are great at blaming themselves for things that are not even remotely their fault. If they have somehow claimed responsibility for their parents' divorce, as in "it must be MY fault they split up," then they wouldn't be at all inclined to accept a step-parent who is just going to absolutely solidify that their parents' relationship is over. My ex hurt my kids in a serious way when he moved across the country when we were still in the midst of our divorce proceedings. My older daughter confided in me that she had asked him, straight out, not to go. She honestly and truly believed that if she asked him, he would stay. And, of course, he left anyway. She was 9 or 10 years old when that conversation occurred and she's never forgotten. She's now 16. There was a huge hole in her heart and her sister (3 years younger) was equally hurt. When my new husband came into the picture and showed them love, took interest in all of their hobbies and activities, chauffered them over hell and high water to friends, events, and more, they were able to accept him as a parent. They are real clear that he is not their father but he IS their Dad. My younger one calls him "Dee Dee"... she says that he needed a name of his own because "Dad" doesn't always mean you're a nice person. What was I going to say? Step-parents can have such a hard row to hoe... I think all they can do is try to be patient, try to listen, understand and hopefully remember that the child probably doesn't "hate you" ... they might just hate the circumstances that brought you into their life in the first place.

I think it has to do with kids not wanting the original parent to be replaced. Many times they go into a situation with resentments already formed, and the step parent isn't really given a chance. Thus, if the step parent does something slightly wrong, it is magnified. Each person is different, so there really doesn't seem to be a "method" to breaking the mode, but rather providing the opportunity for the kid to get to know the step-parent, and realization on the part of the new parent that they need to move slowly.