So this is how I see it. The movie itself shows some kind of lesson of being thankful and content with what you have and such. Looking into the details make it much more understandable on how it is we come to this conclusion.
Getting to know the characters and how they contribute to the story is a good place to start but only selected characters. The movie begins with the making of a Coraline doll with which only the hands of the maker can be seen. Now this scene already tells us that something is not right and this is perhaps because of the fact that the hands we see has needles for fingers making us think that this must be some kind of robot or a machine or something. The sharpness already gives a sign that this character cannot be trusted. The parent characters in this movie portray actual parents in which most viewers can relate to. Both parents work, they are both writers and are pretty much full-on with their career on making catalogs but what they write about is merely something that would sell and pay the bills, meaning they don’t really do what they say, “I can’t believe it. You and dad get paid to write about plants, and you hate dirt”. This is quite typical for anyone who gives advice but I’ll be heading off to a tangent here if I elaborate on that subject. For the most part of the movie, the parents appear to be disagreeable because of how we see them interact with their daughter, Coraline. They do not see eye-to-eye and they do not take her too seriously, pretty much because she is still a child.
At times they even feel bothered and annoyed when she’s around them while they’re working, the mom mostly, “Will you stop pestering me if I do this for you?”. The dad is seems to be more approachable for a girl at her age. But as the story goes on, we begin to change our view of them wherein the mom decides to hide the key of the little door to keep her from harm. We somehow agree with the real mom here because of the belief of her having what we call “Mothers’ Intuition”, which is almost always correct. The mother character chows that even if she is a workaholic, she cares for her daughter and wants to keep her safe. The father in the movie appears to be oblivious of the fact that the ‘dreams’ can harm her and so the dialogue that talk about it does not have any contribution from him except about the monkey slippers.
Coraline, the most important character in the story where without her there is no story, well duh. She looks like a girl who is slightly matured but nevertheless is still young and naïve. Often times in the movie she has had the chance of actually knowing that the other world is not so perfect, too perfect to be real. In her first meeting with the other mother and the other father she’s surprised by their button eyes. But since she is still young and naïve, she is more likely to believe that what she sees is heavenly and so even though she has her doubts, which we can see when the words appear on the cake, she gets distracted and forgets about it. It is only when they offer to have her stay forever that she starts to see things a bit more clearly. She is reluctant of the exchange, buttons for eyes and pain for a ‘perfect world’ and the thought leaving the real world for good is enough to serve as a wakeup call. Or it’s just the disappointment when she was still in the other world after waking up from trying to sleep on the bad news hoping be in her real bed when opens her eyes, “Mom! Dad! …. Oh, God. I’m still here?”. From beginning to end she does have a will of her own and she gets stronger, more confident, and brave knowing that that is the last thing can and must be.
The other mother, also known as the Beldam, is the villain in the movie. But when Coraline first meets her, she’s different but loveable because we can see that she’s sweet to Coraline and shows us that she wants her to be happy. However, we are not a hundred percent persuaded by her because intuition tells us that she is hiding something, a very dark secret that prevents us to fully trust her. It is much more obvious that she isn’t normal because every meal time she doesn’t eat the food she cooks but leaves Coraline to stuff herself up. “Don’t leave me! Don’t leave me! I’ll die without you!” This line has a double meaning. One in which is common for us. It is supposed to make Coraline feel that she’s betraying someone who loves her. But what really means is that if she’s gone then the beldam will literally die for not having eaten her. This makes the cat’s description more plausible, “She wants something to love, I think. Something that isn’t her. Or maybe she’d just love something to eat.”
So yes it does say in the poster, “Be careful what you wish for” even though there is no evidence in the movie that she wished it. But with hindsight we can look back to the scenes that actually show that she willed it. The most obvious one is after she goes school shopping with her mum. She did not buy the gloves that Coraline had wanted and compared her mum to the other mom, “My other mother would get it”. This makes her keen on returning to the ‘perfect’ world.