Subject Lines

🤔 Did you know…

You opened this email for a reason. Well, actually 4 reasons.

I used 4 brainy techniques to coax you to open today’s newsletter.

What are they? Then keep reading…

Special offers for you from our sponsors Storyblok and Upfluence ❤️

Ditch your old, clunky CMS. Modern marketers use Storyblok 🚀

Fast-moving teams need faster tools. Netflix, Oatly, and Adidas use Storyblok’s super intuitive visual editor to build and edit content without constantly bugging their dev team and designers.

​​​→ Don’t get left behind—try Storyblok today

Find creators that speak to your audience with Upfluence 🎯

You know creator partnerships drive revenue… but managing tons of creator and affiliate campaigns can also drive your marketing team crazy. Upfluence simplifies creator collaborations: discover, communicate, ship products, pay, track sales and more—all within one platform. Book a call with one of their experts for free.

→ Talk to an influencer marketing expert today!
(Special offer for Why We Buy readers)

Imagine this…

It’s 11:13 a.m. on a Tuesday.

There’s still plenty of work to do but your brain doesn’t want to cooperate so you take a short break.

You fight the urge to open Twitter X and decide to catch up on emails instead.

As you scan your inbox full of hundreds of unopened emails, one jumps out at you.

It’s from a sender you trust and the subject line catches your eye. Before you know it, you’ve clicked into the email and you’re reading it.

What was it about this email that urged you to open it?

In today’s edition of Why We Buy 🧠 we’ll explore Email Subject Lines  how to write email teasers that actually get opened.

Let’s get into it…

The Psychology of Subject Lines 🧠

Email isn’t new and sexy. It’s been around since 1971. If you’re looking at the whole history of the internet—which was invented in 1969—email seems ancient.

Every year some marketing guru proclaims, “Email is dead”.

And every year smart businesses ignore that dude and generate billions in sales by showing up in their customers’ inboxes with valuable content.

Showing up is just the first step though. You must also earn an open from readers, which is why your subject line is so important.

Someone may be reading emails on the latest iPhone, but they’re using hardware that’s 450 million years old.

(I’m talking about their brain 🧠).

They’re operating on instincts forged long before the digital age.

If you want your emails to stand out in a crowded inbox, don’t just study your competitors or blindly follow “best practices”.

You must first understand how your readers process information and make decisions. That’s how you create un-ignorable subject lines.

Inside Your Buyer’s Mind🧐

The average office worker gets 121 emails each day. Most go unopened.

Your buyers are busy and selfish (we all are). They only want to open emails that benefit them.

When a new email shows up in their inbox, they’re given limited information to decide whether to open it or ignore it.

They’re typically shown:

  • Who it’s from (aka “From Line”)
  • A subject line
  • Preview text (on some apps)
  • Profile photo (on some apps)

Think of an email subject line like a movie trailer. It’s a short teaser with one goal: convince your reader to open and consume the email.

“Good” email subject lines result in higher open rates. But, as with most things in marketing, “good” is highly subjective.

Doing customer research is critical if you want to craft subject lines that resonate with your buyers—it should be your first step. Once you’ve done your research, there are some universal techniques you can try to earn more opens.

How To Apply This 🤑

Alright, so how can you write subject lines that earn more opens?

Use curiosity to coax the click

The “curiosity gap” is one of the most powerful tools in marketing. When there’s a gap between the information given and the information withheld, people want to close the gap.

Using curiosity in your email subject lines is a crafty way to earn more opens.

Biddyco’s short subject line says: “Ad #452 – don’t do this”

We have some information—we know the email is about an ad and it’s from Ben at Biddyco—but key information is withheld.

Suddenly you’re asking yourself, “Oh no. WHAT shouldn’t I do with my ads?” 😬

If you want to close the gap, you’ve gotta click to read the email. Smart, right?

Write for system 1 thinkers (not system 2)

According to Daniel Kahneman, the author of Thinking Fast and Slow, there are two modes of thinking:

System 1 thinking is fast, automatic, unconscious, and emotional. We’re in system 1 mode most of the time.

System 2 thinking is slow, effortful, and logical. We use system 2 mode for more challenging cognitive tasks like solving complex problems or writing.

Embrace delegation

When you’re racking your brain trying to write the perfect subject line, you’re probably in system 2 mode. But your readers will consume it using System 1 thinking.

If you want to grab you’re reader’s attention make sure your subject line is: clear and compelling.

Shorter subject lines that use simple words will often perform best.

Bonus points for using action verbs, emotional words, or negative words. People are biased to pay attention to those sorts of words.

Use pattern interrupts to stop the scroll

Inboxes are crowded every day… but there’s one day they’re overflowing: Cyber Monday.

Nearly every brand is running a promotion and writing subject lines like:

“🚨HUGE SALE!! 🚨” and “Get 75% off – TODAY ONLY ⏰”….

You can copy the pack—and be ignored—or break the pattern to stand out.

Last Cyber Monday I ran a sale on my Clarity Call Cheatsheets.

I knew marketers would be analyzing their own inboxes on Cyber Monday looking for deals and inspiration for future campaigns. So I crafted a subject line I hoped would catch their attention.

This cheeky subject line did the trick. This email had a 58% open rate (on one of the busiest email days of the year) and we did more than $12,000+ in sales on a $99 product.

Be so consistently good the subject line (kinda) doesn’t matter

You can use the most clever subject lines in the world, but…

There’s one line that matters much, much more than your subject line: the from line.

As Ann Handley, wrote on Twitter X in all caps: “YOUR FROM LINE MATTERS MORE THAN YOUR SUBJECT LINE… This is the single biggest thing I’ve learned in two and a half decades as a marketer”.

Ann is right.

Why We Buy 🧠 and Demand Curve’s Growth Newsletter are consistently rated as two of the top marketing newsletters.

We don’t sweat our subject lines. In fact, we both use a repeatable format for every issue.

Embrace delegation

I simply say the topic of the newsletter and remind readers it’s coming from Why We Buy 🧠. Neal does something similar by just numbering each issue.

We don’t need to resort to clickbait-y subject lines because our readers know we deliver valuable emails each week.

We’ve worked hard to build un-ignorable personal brands. Readers trust us.

Our subject lines are the same each week, but we’re still doing some smart stuff to nudge readers to open.

  • We use the preview text to tease the content. Notice the curiosity gap in mine? And Neal is speaking to System 1 brain with his preview text.
  • I use a signature 🧠 emoji every time. I want people to associate our newsletter with making them a smarter marketer.
  • My profile picture is an animated GIF. This stands out in the inbox next to mostly still images. This is distinctiveness at work.

These small brainy techniques help us to earn each open.

The Short of It 💥

Email is still one of the best marketing channels. But getting someone to subscribe to your email list is just the first step.

Smart marketers use buyer psychology to craft subject lines that get their emails opened. Now you can too!

Until next time, happy selling.



Wanna really get inside your buyer’s head?

There are a few ways we can help:

  • Get explosive clarity on what works with buyers with Clarity Calls
  • Build an audience that builds your business. Join the waitlist for the next cohort of the Un-ignorable Challenge (starting October 11th)
  • Apply to sponsor Why We Buy (next opening in Q4)

Written By Katelyn

Katelyn Bourgoin is the CEO of Customer Camp, a 4X founder, and a cheese lover. She lives by a simple mantra: whoever gets closer to the customer wins.

Related Posts

Mental Accounting

Mental Accounting

Let’s explore mental accounting—why we treat money differently based on how we label it.

Beyond Meat

Beyond Meat

Let’s explore Beyond Meat—a brainy business that flipped the entire meat industry on its head…

Expectancy Theory

Expectancy Theory

Let’s explore Expectancy Theory—why our motivation is driven by desired rewards and our likelihood of getting them.

Cognitive Load Theory

Cognitive Load Theory

Let’s explore Cognitive Load—why we make subpar decisions when we’re overloaded with information.



Let’s explore Mood—why our mood heavily influences our purchase decisions.

Rhyme as Reason

Rhyme as Reason

Let’s explore Rhyme as Reason—why we perceive statements that rhyme as more believable than those that don’t.



Let’s explore Tinder—the $42 billion giant that revolutionized dating for a generation.

Messenger Effect

Messenger Effect

Let’s explore the Messenger Effect—why we’re more likely to pay attention to a message when someone we trust delivers it.





Wanna get inside your buyer’s head? Join our newsletter and get one customer psychology tip delivered straight to your inbox each week. It’s like a 2-min workout for your brain.

You're in. Giddy up! 🤠

Become the go-to customer EXPERT

If you can figure out what makes people tick, click and buy, you can make bank

We’re often asked if we offer a certification program teaching our in-depth research methods. The answer is… not yet. But we’re working on it.

Want first dibs when we launch our new certification program? Jump on the waitlist.

You're in. Giddy up 🤠


Wanna get inside your buyer’s head? Join our newsletter and get one buyer psychology tip delivered to your inbox each week. It’s like a 2-min workout for your brain.

You're in!


If you can figure out what makes people tick, click and buy, you can make big $$$. We're working on a new research certification program. Want first dibs when we launch it? Hop on the waitlist.

You're in!


Wanna get the buyer insights you need from key stakeholders (and look like a boss)? Our new Stakeholder Mining Kick-off Session training is coming soon. Join the waitlist to get first dibs.

You're on the waitlist! We'll reach out soon!


Wanna get the buyer insights you need from key stakeholders (and look like a boss)? Our new Stakeholder Mining Kick-off Session training is coming soon. Join the waitlist to get first dibs.

You're in!