You've heard it a thousand times. Maybe you said it this morning. "I’ll let you know." It sounds harmless, right? It’s the ultimate social lubricant. It buys you time when your brain is fried and your calendar looks like a game of Tetris played by someone who is losing badly. But here’s the thing—honestly, it’s usually a lie. Not a malicious one, but a lie of convenience that creates a massive amount of "open loop" anxiety for everyone involved.
We use it to dodge commitments without the awkwardness of saying "no." It feels polite. But in the world of modern psychology and high-stakes business, this phrase is increasingly viewed as a red flag for poor reliability.
The Psychology Behind Saying I'll Let You Know
Why do we do this to ourselves? Humans have a hardwired desire to be liked. Saying "no" feels like a social rejection, and our lizard brains scream that rejection equals being kicked out of the tribe and eaten by a tiger. So, we pivot. We use I’ll let you know as a safety valve.
Dr. Susan Newman, a social psychologist and author of The Book of No, often discusses how people-pleasing creates a "yes-man" culture that actually erodes trust. When you tell someone you'll get back to them, you aren't just delaying a decision; you’re creating a cognitive debt. This is known as the Zeigarnik Effect. This psychological phenomenon suggests that our brains remember uncompleted or interrupted tasks better than completed ones.
Every time you utter the phrase, you’re basically opening a new tab in your brain’s browser. Do that ten times a day, and your mental processing speed starts to crawl. You’re stressed because you have ten people waiting for an answer you probably already know is "no," and they’re stressed because they can’t move forward with their plans.
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Why This Phrase Destroys Professional Credibility
In a professional setting, "I’ll let you know" is often the kiss of death for a deal or a promotion. If you’re a freelancer and a client asks if you can take on a project, saying those five words is basically telling them, "You are my second choice if nothing better comes along."
Real experts don't waffle.
Think about the most successful people you know. They are usually decisive. They either say, "Yes, I’m in," or "No, that doesn’t fit my current capacity." When you leave things in limbo, you're signaling a lack of organization. It suggests you don't have a handle on your schedule or your priorities.
I once worked with a project manager who used this phrase as his default setting. He thought he was being flexible. In reality, the entire team was paralyzed. We couldn't book vendors, we couldn't set deadlines, and eventually, the client pulled the contract. They didn't leave because he was mean or bad at his job; they left because they couldn't stand the uncertainty.
The Hidden Power Dynamic
There’s also a subtle, kinda gross power play involved here. By saying I’ll let you know, you are effectively putting the other person’s life on hold. You are the gatekeeper. You hold the information, and they have to wait for your permission to move on.
It’s a low-key way of asserting dominance that usually backfires by making people resent you. If you’re doing this to friends—say, someone asking if you’re coming to their birthday party—it’s even worse. You’re essentially saying your time is more valuable than their planning efforts.
How to Stop the Waffling (And What to Say Instead)
Breaking the habit is hard because it’s a reflex. It’s like saying "bless you" when someone sneezes. You need to replace the reflex with something functional.
If you truly don't know the answer because you need to check a specific variable—like your spouse's schedule or a budget report—then be specific. Specificity kills the "open loop" anxiety.
Don't just say you'll let them know. Say, "I need to check my calendar for Tuesday; I will give you a hard yes or no by 4:00 PM today."
See the difference?
You’ve set a deadline. You’ve taken the burden of the "follow-up" off the other person. You’ve shown that you respect their time enough to give them a timeline for your indecision.
The "Gentle No" Strategy
Most of the time, we say we'll let someone know because we want to say no but don't want to be a jerk. Here are some real-world alternatives that work way better:
- "I’d love to help, but I’m at my limit this week, so I have to pass."
- "That sounds like a great opportunity, but it doesn’t align with what I’m focusing on right now."
- "I can’t commit to that, but check back with me in three months."
These responses are final. They are clean. They allow the other person to move on to the next candidate without feeling like they are "waiting" on you.
The Cultural Shift Toward Radical Transparency
We are living in an age of information overload. Our attention spans are shorter than ever, and our tolerance for "fluff" is at an all-time low. People crave directness.
In Silicon Valley culture, there’s a growing trend of "radical candor," a term coined by Kim Scott. It’s the idea that being direct—even if it feels a little blunt—is actually the most empathetic thing you can do. By avoiding I’ll let you know, you are practicing a form of micro-honesty that builds massive long-term trust.
When you are known as the person who gives a straight answer, your "yes" becomes much more valuable. People know that when you agree to something, you’re actually going to show up. Your reputation becomes one of "high integrity" rather than "well-meaning but flaky."
Actionable Steps to Reclaim Your Schedule
If you want to scrub this phrase from your vocabulary and actually improve your relationships, start with these three things tomorrow morning:
- The 24-Hour Rule: Never let a "maybe" sit for more than one day. If you can't decide in 24 hours, the answer is almost certainly no. Just send the text.
- Audit Your "Open Loops": Go through your texts and emails. Look for every time you said you'd get back to someone and haven't. Close them all right now. Even if the answer is "Hey, I totally forgot this, and I actually can't make it work."
- Check Your Gut: Usually, we know within three seconds if we want to do something. If your gut says "ugh," but your mouth says "I'll let you know," stop. Breathe. And say, "I don't think I can make that work, but thanks for asking."
Being decisive isn't about being bossy or mean. It’s about being clear. Clarity is kindness. Every time you avoid leaving someone in the dark, you’re making the world a slightly less chaotic place.
Stop being the "let you know" person. Be the "here is the answer" person. Your stress levels will thank you, and honestly, your friends probably will too.