Bad Email Subject Lines that Hurt Your Open Rates (17 examples)

Bad Email Subject Lines

It’s true that bad email subject lines will make subscribers ignore your emails. 

Good subject lines get emails opened and eventually lead to sales and conversions.

So how can you be sure to avoid bad subject lines that hurt your email marketing?

Well, just take a look at the terrible ones below and don’t write any bad email subject lines that resemble these boring, spammy, unrelatable, and unclear lines that are in my inbox!

(I’ll save the worst line for last)

Bad Email Subject Lines: Boring Ones

Ok, compare these two subject lines and see which one you would have opened.

Your daily estate sales on


Shark pulls man off boat, a gator and Twisted Tea, and the troll apartment

Pretty easy choice, right? The top one isn’t the worst email subject line. I mean, I signed up for the emails, so I have an interest in the message. But it does not grab my attention. It’s too general, making it boring.

Now, two more subject lines to compare.

Apple has declared war on email newsletters


Money Matters – invitation

Hey, I’m into money and like getting invited. But what makes the bottom one a bad email subject line is the lack of motivation. Whereas the top line screams ‘read this now’! It’s appealing with power words and tangible dangers to those in the email marketing world.

Bad Email Subject Lines: Spammy Ones

Spam works or spammers wouldn’t waste their time. 

But most people roll their eyes when the spammer uses an obviously spammy phrase or foolish font or weird wording.

See what I mean below with the 8 lines covered in the stench of spam: 

Bad Email Subject Lines

Bad Email Subject Lines
Bad Email Subject Lines

Thankfully, none of those bad email subject lines made it to my inbox. Most were in the spam folder without me having to even glance at them.

That is a key lesson. If you have any subject lines that even sniff of spam, don’t be surprised if your open rates fall fast and hard. Spam filters can kick your emails out of the inbox even if you are sending legitimate marketing emails.

Please keep your subject lines clean and make sure they don’t resemble anything spam-related.

Bad Email Subject Lines: Unrelatable

Let’s compare subject lines that appeal to my interests versus ones that just don’t matter much to me.

More Rate Hikes Expected


AI Is Hurting the Climate in a Number of Non-Obvious Ways

First off, the top line is no shocker and I can’t do anything about the Fed’s rate hikes. Plus, I’m not house or car shopping.

The bottom one is a good subject line because AI matters to my industry. And I kinda like Earth not getting jacked up.

What about the next two subject lines?

Suspect wanted in multiple counties in custody


Midweek pick-me-up: The science of sleep

The top line should have a better chance to hook me than the bottom one. See, the top line is from a local news site but I don’t care for 6 o’clock ‘if it bleeds it leads’ news. So the website should nudge me to choose news updates I do want.

The bottom subject line gets me to check it out because I do care about sleep. My sleep, to be clear! So that info will help me more than a random police report. 

Bad Email Subject Lines: Unclear Ones 

Here are a few bad subject lines and I’ll explain why they are unclear.

1️⃣Dante’s Inferno: Canto XXVII

This one is on me. I vaguely remember signing up on Substack but maybe their welcome email didn’t explain exactly what I would be getting. Keep this in mind with your email sign-up forms and welcome emails.

Be sure subscribers know what your emails are about and when they will receive them. 

2️⃣US Supreme Court Goes 9–0 in Surprise Ruling

Curiosity usually works in subject lines but in this case, heck, there are tons of Supreme Court Rulings and I have no time to keep up with them all. So, maybe if they included which case, then I may have opened the email.

3️⃣boosting revenue in H2

H2’s meaning isn’t obvious. In this message it means the 2nd half of 2023. It could’ve been referring to a program or investment of some kind. Now, I would have opened it anyway since I like Mailshake’s emails… if I had time to notice who it was from.

4️⃣Reminder: New ‘before & after’ photos | My top 10 favorite cleaning products

Why is this one a bad subject line? It’s the beginning that hurts the chances of it getting opened. It’s unclear what type of before & after photos are inside this email. Unless I glance at the sender (whom I enjoy), I probably won’t open it. Despite the last part of the subject line being intriguing (numbers help).

Let’s wrap up with a summary and the absolute worst email subject line I could find. 

Bad Email Subject Lines Summed Up

Sadly, there’s no guarantee that your best subject line will get superb open rates. 

Subscribers are busy and distracted. Plus, there are other factors at play, like fickle spam filters.

But when you avoid bad subject lines, you greatly increase your chances of getting more opens and engagement. And that’s the goal in the email marketing world.

  • Good subject lines don’t confuse your subscribers or put them to sleep.
  • They don’t include endless exclamation marks or crazy fonts. 
  • Good subject lines have something the specific reader wants or cares about (segmentation)

Subject lines are like other vital factors in email marketing strategies. You have to constantly work on them, tweak, and test them.

Just bookmark this page so you can check back as a reminder to avoid the worst types of email subject lines.

Dead email lists are a different story though…

How much of your list is dead in the water? The best subject line ever may not re-engage inactive subscribers. 

Imagine resuscitating those “dead” email subscribers and bringing them back into the purchase funnel. Inbox Mailers prompts re-engagement. Our platform leverages a patent-pending engagement trigger system that we have seen double and even triple open rates. Book a free live demo and learn how Inbox Mailers can revive your dead list.

*Almost forgot that absolute worst subject line… here ya go…

“You just won $2,500.00 from CASINO-TITAN 𝙋𝘼𝙔𝙈𝙀𝙉𝙏: JOHNGARDNER✅💲”

Spamtastic! Zero chance of landing in any inbox or getting opened. 

Bad Email Subject Lines
John Gardner

John Gardner

John Gardner is an expert email marketer and co-founder of Inbox Mailers. He specializes in email segmentation and improving overall deliverability, helping top brands and businesses optimize their email marketing strategy.