It is not entirely about hiding evidence of abuse. They need it to be able to keep deluding themselves into believing that there’s nothing wrong with them.

A narcissist or a psychopath don’t pretend that they’re the nicest people on earth to strangers or everybody that knows them in order to hide the fact that they are abusing their victims behind closed doors only. They do so in order to obtain positive supply or fuel as well, comprised mainly of feeling good about themselves because others perceive them to be good people or good at something. They don’t have to receive compliments on the daily. They just have to be perceived as amazing people who are spectacular in every way by everybody but their victims. That makes them feel good about themselves. They need that to maintain their delusion of being amazing despite all evidence pointing to the contrary. And that is why they need that positive supply or fuel, because they can’t have any evidence to support their claims that they are awesome and amazing except from believing that all others believe that they are really that good. They can’t survive without such false or fabricated evidence because they can’t demonstrate any other evidence, whether strong or weak evidence, in order to support those grandiose beliefs they have about themselves. And they will find none, even if they wanted to, no matter how hard they try, for a simple reason: they are trying to prove something that is absolutely and totally false and doesn’t exist. It’s not a matter of something that is true that they cannot seem to find evidence for it, it’s a matter of something false that they themselves know that it is false, but they try to delude themselves into believing otherwise by manufacturing false evidence or unreliable evidence for it. As you can see, the reason they are hell bent on obtaining positive supply from other people has little to do with hiding the fact that they are abusing you behind closed doors. As you are always told, don’t take it personally. They will try to pretend to be the opposite of what they truly are, with or without you. With or without abusing you. They are not so related. Making other people less suspicious of the abuse going on behind closed doors is almost only a byproduct. They need to feel good about themselves through delusional methods or pathways anyway, because they can’t obtain that self-esteem from within, because they have no ego. There’s no self to feel confident about in the first place. They are too immature to face the truth. Whatever truth that feels inconvenient, they move mountains to deny it, because they can’t face it like a grown-up.

You might be wondering, why would someone who is invested in obtaining such huge amounts of positive fuel or supply do everything in their power to not get any of such fuel or supply from you, the individual they’re abusing behind closed doors? The answer is simple: they are getting that positive fuel or supply from you, and plenty of it, every time you pay attention to them. Every time you interact with them. Every time you engage with them. And when they have enough of positive fuel from you, they switch to seeking negative supply or fuel from you. The devaluation. The discard. They need to hurt you, in order to feel good about themselves. Since they can still hurt you, then that means that they’re so amazing to the extent that they can hurt you. For some reason they feel competent, important, superior, amazing, strong, worthy, valuable, skilled, talented, or good enough just because they were able to hurt or harm you one way or the other. That gives them negative fuel or supply. And they can only do so to their victims, because other people will not allow them to get away with such treatment. Other people will never tolerate that kind of behavior. Because other people have options, but you’re simply stuck with them with nowhere to go. You cannot escape the abusive situation right away, and that is why it’s happening to you. It’s not that if they kept exclusively abusing you, you’ll definitely leave them for good, so they have to balance that with some good days. It’s because part of the humiliation is to abuse you to the fullest, and then manage to convince you to stay after all this. And thus, in this case, the good stuff that they did that made you stay, is only part of the abusive experience. It is still a major part of the abuse that they intentionally exercise upon you, because they obtain self-esteem from the fact that they were still capable of making you stay after all that abuse. They are aware of this, and it makes them obtain positive fuel or supply, because it means they’re so dangerous and superior they can control you to no end, to the extent that they can force you to do the impossible: stay after having gone through all of this abuse from this specific individual. Manipulating you, is part of what makes them feel good. That’s why they lie about stuff that doesn’t matter. That they don’t have to lie about. Managing to manipulate you makes them feel superior and so good. And it proves to them that you’re totally under their control, which means they have secured an endless source of fuel or supply, at least for the time being. Everything is part of the plan. You perceiving the good days as a sign that there’s still good in them is a source of positive fuel and supply for them. It makes them think they’re so good they can mislead you to that extent. They are so good they’ve managed to make you believe that the good treatment isn’t an essential or integral part of the abuse. You are now gaslighting yourself. They have managed to manipulate you that much and to that extent, which gives them positive supply or fuel, because it makes them feel superior enough. It makes them feel better than you and better than everybody. Still, hurting you might serve as pure negative fuel or supply for them, because seeing you in pain makes them feel good, gives them pleasure and reward, even if it does not necessarily mean that they are so great or amazing. They are directly rewarded through harming or hurting you, or causing you pain, with or without that indicating that they are so superior or that they should feel good about themselves because they were capable of harming or hurting someone, or causing someone to be in pain.