Well, lately I have come across a variation of the following sentence a lot:
"Harry Potter is better than Twilight because Twilight gives a lot of bad messages"
I won't deny the message given by Twilight is an awful one and easy to spot, but Harry Potter also has its share of bad messages, and whats worse is that it is conceived between lines. There's an extense debate among psychologist on the validity of subliminal messages, but that I will not discuss.
Following I will list, in my opinion, the (bad) messages each book gives.
Let's begin with the easier one, Twilight:
1. Looks tell a lot about people. If he looks charming he is bound to be a good person who deserves your complete love. Pay not attention whether he is a killer or a pedophile, God wouldn't bliss him with beauty unless he is a good guy.
Explanation: this message appears throughout the whole book demonstrated by Bella's love toward Edward despite him being a vampire who has lust for her blood. Whenever a flicker of fear pops in Bella's mind it is quickly sweeped away but her thinking "How can someone so beautiful be bad?". In real life, the prep team's handsome coreback beating the crap out of his girlfriend has become such a cliche that developing the point any further would be redundant.
2. If you are smart you should show it off. Vanity and arrogance makes you all the more appealing.
Explanation: Edward having lived for 100 years knows a lot more than teenagers his age. And he constantly shows it off and diminishes Bella, considering her foolish and clumsy among other things. In real life, if you show off your inteligence you don't get love, you get your money taken from you at lunch.
3. It's ok to use people who have feelings for you as long as you fealt guilty for a couple of minutes before using them again.
Explanation: The whole Jacob-Bella relationship. He really loves her, and she knows this, thus she turns him on in order for her to get what she wants (information about the cullens, bikes repaired, help in vampire *war*). In real life, though you may get what you want by doing this, you will also draw a bad reputation towards yourself.
4. The more mean he is to you, the more he loves you.
Explanation: Edward is always pointing out how stupid Bella is and clumsy and how much he wants to eat her. To top it all he leaves Bella after a papercut, but yet torments her by appearing when she is about to do something reckless, in turn turning her into an "adrenaline junkie" as they refer to in the book. They have catalogued this as true love. In reality, it's a mix of slavery with psycholigcal torment. Diminishing a woman in order to have her do what you please, then dumping her but still appearing every so often is a classical movie plot. And as we see in those movies, this ends mentally demolishing the woman.
5. If the guy you love leaves you, keep trying to hurt yourself. He will eventually come back. Also if the girl you love doesn't pay you attention keep insisting on her till she realizes she loves you a bit.
Explanation: Bella jumping off a cliff in order to get Edward back. And then Jacob sexually assaulting Bella and menacing her to commiting suicide so that she realizes she loves him too, but loves Edward more. In twilight this is love. In real life, this is a mental disorder: obsession.
6. You are a burden to your parents. You stand in the way of your mother and his new boyfriends happiness so you better leave. And if your father gladly takes you in and worries about you, he is annoying and you have to hate him. After all, he could have tied your mom to the bed in order to prevent her from leaving.
Explanation:On the first point, among the first few pages of Twilight Bella says that she didnt want to leave, but wanted her mother to be happy. Later she says they are best friends. So, how can she not be happy with you around? You came out of her!(Sorry if this sounds disgusting, however if you read Breaking Dawn where Reneesme is born your stomach probably is already used to this).Then on to the second point,I didnt do research on Meyer's life. The whole Charlie-Bella relation reeks with parental trauma. Charlie worries about Bella, and she considers that annoying and hates having to go to live with him. Well, he is head of the police office. He sees a lot of things in the street, so he is bound to be worried about her only close relative. And somehow, Meyer also found a way to portray CharliestillbeinginlovewithRenee as something bad that should be spourn on. I mean, look at that guy how pathetic he is for loving someone in a nonobssesive way like Bella does.
7. Have a backup group of friends. You don't really have to like them, in fact, if they are your backup friends it means they are not cool. When your main group of friends is around, pretend the backup doesn't exist.
Explanation: Since 1st day in school, Bella gave us an insight of how dull, boring and mentally inferior the students in her new school were. Look at them, they are, what, 17 years old and having a snowball fight? What a bunch of freaks. And then, Bella gets "in love" with Edward and becomes a part of the Cullen, and leaves the first people that talked with her and were kind aside. Then the Cullen's leave and she goes back with Mike and Jessica. Then Jacob becomes a wolf and he hangs out with the wolf pack, leaving his backup friends again. Then Edward comes back, and as of halfway through Eclipse we have to assume Mike, Jessica and the rest fell through a vortex into a parallel dimension cause they are hardly ever mentioned again, only from time to time to remind us how annoying they are for trying to be friends with Bella. I mean sure, you can try to get along with everyone but have some close friends. But if you neglect the existence of anyone else, then come running back when you are all alone and dump then again, don't be surprised if you end up all alone. People in real life don't like being used around.