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How to AI

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How to train ChatGPT to write like you.

Ruben Hassid's avatar
Ruben Hassid
Oct 29, 2025
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No one told you how to train ChatGPT to write like you.

So I will.

This is not about one simple prompt to get perfect writing.

This is all about teaching your own writing style to ChatGPT.

At the end of this newsletter, you will master:

  • How to remove the infamous—em dash.

  • How to stop ChatGPT from agreeing with you.

  • This prompt to instantly write with (your) taste.


Remove the em—dash.

ChatGPT loves em dashes.

And it’s really hard to remove them:

Every single day I tell GPT to never use em dashes, but GPT doesn't care  what I want. : r/ChatGPT

So much so that it became even the symbol of ChatGPT.

The em-dash is now the number one way people can tell if something’s written by AI. Some call it the em-dash conspiracy.

How to remove em dashes from ChatGPT | Ruben Hassid posted on the topic |  LinkedIn

Okay, we do know there is a problem with em-dashes. Even if you love them, there is a high chance you want to remove them because the fact that it’s here makes it sound like you use AI.

And you don’t want to.

Because the whole point of using AI is to keep your taste and your tone of voice. And the problem is that the em-dashes—even if you love them—ruin this away.

Let’s make a quick step-by-step guide on removing the em-dashes.

Step 1: Go to your Custom Instructions.

In your bottom left menu on your face, go to “Personalization”.

Then found “Custom Instructions” after enabling them.

Step 2: Add this specific line.

Here’s the magic prompt:

Systematically replace em-dashes (“—”) with a dot (”.”) to start a new sentence, or a comma (”,”) to continue the sentence.

I made a test before/after adding this specific prompt.

without the right custom instructions

with the right custom instructions

You might make the mistake of thinking that it was as easy as prompting, “Please stop using em-dashes”. But it’s not.

You actually have to give ChatGPT an alternative to using them. Otherwise, it will keep using it.

Now that I said you can use dots or commas and that I prefer short sentences, it’s working!

You might say that now the sentences are too short, but it’s up to me to change the custom instructions, and I know that it will always systematically change the em-dashes to either commas or dots, and I guess that’s your goal.

Personally, I like em-dashes.

But AI ruined it in people’s psyches.

Still, people write with em-dashes:

We did it —we removed the em-dashes, and now you can use them or not as you please. But can we stop ChatGPT from agreeing with everything?

Well, that’s a different topic. Let’s dive in.


Stop ChatGPT from agreeing.

This one came to me from a tweet, and I had to test it out:

And I have to say, I’m impressed. It works:

ChatGPT directly disagrees with me. And it explains the reason in almost a robotic way. That’s because my custom instructions are made for me.

And I am an ENTJ. I love robotic talk. I like when someone is direct, straightforward, doesn’t sugarcoat, uses very little emotion, and goes all in on rationales.

Copy my custom instructions at the end of this newsletter. It’s a paid, member-only perk.


Copy this to instantly write with (your) taste.

You now know how to remove emdashes, to stop ChatGPT from agreeing with you. But how do you make ChatGPT right, like you and no one else?

Because that’s the key.

I just recorded a Facecam video of how I feel about writing your best work, with taste, using AI. It’s all about avoiding AI slop with this simple prompt framework.

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