Now the media has a strong influence on how you perceive the world especially who you consider good/bad people. Think back to when you were a little kid, you were constantly being bombarded that the good guy/gal were good looking and the bad guy/girl were ugly.
So at a young age you already have a subconscious association that people you meet that are good looking are good guy/girl by default. Your naturally incline to be swayed to that level of thinking until proven otherwise.
And a perfect case of where that mental image u have just from looks is broken is when you walk up to a good looking person and their personality does not match the personality/behavior of a good guy/girl (e.g. he's an asshole/she's a bitch). Your brain is able to shatter the image/belief you've form of them and you can see them as real people.
Now this level of thinking becomes very dangerous when you meet a person who is not only good looking, but matches the personality of appearing to be good person.
Let suppose you meet a girl named Amanda.
Amanda is not only beautiful but she puts on a good girl act of being sweet, caring, and is soft spoken. It's at this point your brain is telling you that she is a good person by default and your already forming up her morality, sexual history, behavior, honesty level just from your very short meeting with her.
So this virtual Amanda your brain has created has a strong imprint in your head and even though she is going to exhibiting red flags from further interactions, your going to miss them, or go into denial that they exist because you REALLY WANT to believe she is THE GIRL IN YOUR HEAD and not at all human being with faults and shitty habits.
So let's look at REJECTION PHASE and the DATING PHASE and how you can miss up all these red flags.
Bitch that's the number from the movies: So you had a pleasant conversation with Amanda and you ask for her number. She gives you a fake number because she didn't want to kill the mood by rejecting you on the spot. So you call the number later and realize it's not going through. Your brain already starts making excuses for her like maybe she gave you the wrong number, wrote down a wrong digit or her hand writing was bad and that 6 is really an 8. You can't come to the realization that she rejected you and lied because in your head Virtual Amanda doesn't lie.
Texting Phase: So let say she did give you her actual number and you start texting her. She is using you for attention and to entertain her when she's bored but you can't see it because you think she's a good person who doesn't use people. So she replies back to your messages whenever she has nothing else to do. Some days you are waiting hours/days for a response. If you call her out on it she spins a BS lie about her phone giving trouble or how she is now seeing the message and you eat it all up because she apologizes sweetly and even include smiley faces.
She might also be mentally unstable and like to make up lies about things that never happen in her life to get sympathy/attention from you and your eating this all up because you think she is honest and the very though of her being capable of lying for such a silly reason hasn't even registered yet.
[At this point if it was anyone else you would realize your being disrespected, see the red flags, and realize this girl doesn't give a fuck about you but she puts on the sweet act so well, and is pretty that your eating up all her BS.]
Even with asking out on a date she will lie to get out of the date, or come up with an excuse but she'll say it in such a way that if you ask her out at a later time she'll say yes. She wants your attention but not you and your being lied to but you can't believe that such a nice person would do such a shitty thing because you've placed her on a pedestal.
So you see during the rejection phase she's been mentally abusing you, lying to you and using you. However, a combination of the halo effect (good looks) + nice girl behavior has clouded your brains judgement into thinking she's a good person, created an image of her in your head, and despite all these negative signs that the relationship at this point is unhealthy and you should drop her, you keep making excuses for her.
Now going back to sexual history, morality, habits. In your mind virtual Amanda does not sleep around, she probably only gets into LTR and not into ONS, doesn't like doing drugs,smoke, drink excessively etc. And you could very well be dead wrong. The real Amanda despite acting sweet could very well be sexual open and likes to sleep around, take love drugs like molly, and smoke.
Casual Dating: Let say you started dating her and she sleeps with you on date one.
In a logical thinking mind that hasn't had its reasoning compromised, you'd be asking yourself that if she does this for you then how many other guys has she done this for. And you'd pick up on another possible red flag of her being slutty but you don't because your brain is still trying to hold onto the fake personality.
So you start rationalizing that she did it for you because you guys have a special connection and this was a once in a lifetime occurrence that she doesn't normally do. Similar, you might think she is a lady and rather play things slow and not try to make a move that you would sooner with other girls. Not realizing that this girl could very well have no problem with casual sex and is in fact seeing multiple guys besides you. So in between your date sessions she is having sex with other guys.
And all the signs are there that she's seeing multiple guys besides you but you just don't want to see it because you think she is just too good of a girl to do that.
So let say you get this far with her. Despite all the red flags popping up from your first interaction with her to now that you've rationalized away, mentally blocked them out, even altering your own memories of past events and made excuses for her so you don't ruin the image you have in your head of her being a decent, kind girl who would ever do terrible things to people.
You let her get away with a lot of shit and she knows it and she realizes she has a hold over you and can control/manipulate you. So she continues using the act, maybe even putting on tears to get her way and your not seeing what's happening to you. It's only when you've settled into the relationship and you become less phased by her looks that you begin to start thinking rationally again.
All the red flags that you were ignoring, denying, and wishing away in the past starts flooding your memories, your finally see the bad traits and realizing this person isn't really a good person but one who is fake nice and eventually that image you held onto of virtual Amanda breaks and you see Real Amanda.
[A similar case occurs with women when they see a good looking guy, who acts like a good guy. All the signs are there, and the red flags are popping up that this guy is terribad for you but you keep making excuses for him, and rationalizing them away until one day you get past his looks and realize you are dating/married to a complete nightmare]
Now this take isn't saying you need to be prejudiced against good looking people who act nice or that there is no such as a good looking person who has good character. The point that's trying to be made here is that YOU as an individual tend to be so wrapped up by the image presented in front of you and what they are selling that you tend to lose your common sense and ability to think clearly.
You miss out/rationalize away on all the signs indicating to you that the person you've placed on a pedestal is less than perfect and/or bad news to get into a relationship with them.
We tend to have a natural inclination to associate good looks with good character. We automatically place very good looking people in the good person category just from looks alone. Amplifying their good qualities while at the same time either ignoring or underplay their bad qualities. And because of this we let good looking people get away with a lot more things before we place them in the bad person category. The only instance when this is not the case is when they are a bitch/asshole to you right off the bat. In fact them acting this way often cause people to think they are less attractive.
With people who about average in looks we tend to give them a fair shot and have a neutral stance. We look out for their positive traits/negative traits and weigh them fairly before passing judgment on whether they are a good person/bad person.
Ugly people we tend to have a neutral stand point too but tend to have the opposite effect that we have with very good looking people. We overlook and underplay their good qualities while actively seeking hard for their bad traits and when we do find them tend to exacerbate them in our mind. And so we label them as bad people for meager offensive that we let more attractive people get away it.