I know how easy it can be to fall into the trap of oversharing with people, but there are wrong people to do that with, and narcissists fit that mold perfectly.
When you pluck out certain things about yourself to tell the narcissist, you're not just giving them an entry into your vulnerable side, you're giving them permission to store personal details.
This is a type of data sharing that should never be allowed, but narcissists make themselves seem so approachable.
I advise you to never tell a narcissist these five things about yourself.

#1 Whatever you're most ashamed of
We're going in big, but I promise you, you won't want to tell the narcissist anything that you feel the most ashamed of.
Shame is the type of emotion a narcissist loves to know that you can feel, and if they know what triggers it, this gives them an enormous upper hand for the future.
Think about it, you've just told the narcissist that you're ashamed that you once had a habit of shouting in anger during arguments instead of dealing with them with more care.
You are telling the narcissist that you handle conflict poorly, and you wish you didn't.
What you've gone is successfully tell them that whenever they play their own card of conflict, they know you won't handle it well.
It's like saying:
You can go ahead and push all my buttons, and I am warning you now that I will probably react really badly.
That's exactly what the narcissist wants to hear, in fact, it's pure music to their ears to know that you're so reactive.
Letting the narcissist know your innermost imperfections will only serve them.
You think you're sharing and caring, and you assume they're listening and being authentic.

They aren't.
They're taking notes.
#2 Your worst and deepest fears
Ask yourself this question right now:
What are fears?
Fear is an emotional state that leaves you feeling potentially much discomfort, but fear is subjective.
For you, you might fear heights, but I may love them. I may fear spiders, but you might have several arachnid pets!
The bottom line though, is that fear is whatever it is in your life, and it's a huge mistake to tell a narcissist yours.
They will not stop trying to make you feel uneasy, using your fear as the tool.
If you fear flying, don't think for one second the narcissist won't try to push you into booking a flight somewhere, or even doing it without asking you.

They won't hesitate to bring up your fears in front of other people, too; questioning what it is you're scared of and why.
They will look quizzically at you, as if there's something wrong with you.
There isn't.
Fears occur within so many of us, and yes, they are all different.
But as soon as the narcissist catches wind of your own fears, they will use them against you at every single possible opportunity.
It's their way of keeping you afraid, and telling you in no words similar that you're silly, or overreacting, or that 'there's nothing to be scared of.'

Narcissists can also forget (conveniently) that you have a fear, and in turn be the cause and cure to it.
Oh my goodness, I totally forgot! Please come here and let me hug you!
No. The narcissist is not your abuser and your savior. Remember that.
#3 Anything financial that you just can't help yourself with
Cut it out. Just keep it quiet. I know we all have weaknesses, but we learn to moderate our spending and try not to tell the wrong person.
The thing about not being able to help something you want to buy is that you're telling somebody, a person who is very vain and possibly irresponsible with money, that you get caught up in certain materialistic desires.
It's like saying:
I can spend and spend if it's this, and I really am aware of it.
The narcissist's eyes widen as they excitedly think about all the times they'll be able to talk you into buying unnecessary things, and that can only end badly, right?
It's better to know what you need to work on, and keep it to yourself.
If you don't, you're likely going to end up in a whole heap of trouble with the narcissist, especially when they decide on taking you down with them.
Suddenly, it's your fault for overspending. How dare you. Did you not think before you made the purchase?
Remember, telling narcissists these things about yourself for you, is sharing. For them, it's learning all the ways they can manipulate you in the future.
Do you want that?
#4 Anybody who you dread losing or falling out with
You may as well hold a sign up saying:
Please ensure you come between me and this person because it will affect me greatly and you will win.
That's what a narcissist is thinking when you're telling them how close you are with your sister, or how you and your best friend have been there for each other since you were nine years old.

The narcissist isn't sentimental. They won't care about your bond or connection.
They just care about harming you, and isolating you. This is obviously eventual; it'll never happen right away.
There needs to be time to deliver the blow that you're going to lose touch with these people, and it will slowly transpire to be the case.
Sadly, this is a dangerous ploy to keep you to themselves, so you have nobody else to rely on or to support you.
This is why so many abuse victims look around one day and realize that nobody they once held dear to them is even remotely in the picture, it's no accident.
The narcissist is responsible, and they do so by triangulating you.
They convince you that you're too good for them, or they start to get under your skin with comments that annoy you about that person until you finally cut the cord.
Keep your friends closer than this enemy you have introduced into your life.

#5 Any plans you have
Have some nice plans scattered into the future, do you? Well, you'd better just see them for what they are: a big old dream that will never happen the way you want them to.
The narcissist wants to hear all of what you hope, so they can find ways to sabotage each and every single one of them. That's what they love to do.
They want you to dread anything good that's coming. They want you to cancel it if at all possible.
They want you to feel miserable as you attend to your plans. They talk you out of going altogether. They pretend to be unwell and guilt you into looking after them.
Your plans should be, and remain, sacred. If they aren't, then the chances are, you've overshared with the narcissist, and they've somehow got in them idle of them all.
That's where you learn a hard lesson: never let a narcissist know your plans if you value them in any way.
