We all have our own Patronus.
In the Harry Potter universe, when the terrifying Dementors, the creatures that suck out all joy and hope, approach, there is only one way to chase them away: by evoking the happiest, most comforting memory, the one that brings you instant peace.¹
For a long time, I thought I knew exactly what mine was. It always found me in the middle of sleepless nights. The image was of me, as a child, spending long summer days in the pool with my best friends. No set time to leave, no commitments, no worries. A sense of eternal vacation.
But one of those nights, something hit me. Were those days always snapshots of a picturesque “eternal vacation?” How many times, in that same pool, did I not argue with those very same friends? How many times did a subtle comment hurt me so deeply that I couldn’t enjoy the rest of the day? Or I had to begrudgingly leave a game to care for my little sister, while the others kept playing? And yet, this memory, which seemed so solid and so perfect, always showed up without a single crack.
That was the exact moment it clicked. My “Patronus” was not a faithful photograph of the past. It was an edited memory, carefully polished by my own mind.
We always hear that the past helps us to build the present and shape the future. But that phrase leaves out an uncomfortable truth. The past is not a framed painting, nor a movie paused on a scene. The past, in fact, can be just as abstract as the future and often depends on the interpretation and recollection of our current selves. ²
This is because memory isn’t static; it’s malleable.
How Memory Rewrites Itself
Studies on reconstructive memory show that our current emotions, beliefs, and life experiences shape how we recall past events. Cognitive psychologist Daniel Schacter notes that this transformation is not merely about forgetting or distorting, but about integrating new meanings into old experiences, a kind of narrative updating that reflects who we are now, not who we were then.³
One of the clearest illustrations of this phenomenon is rosy retrospection—a bias that makes us remember the past as happier or easier than today.⁴ In moments of sadness or discouragement, it leads us to revisit old experiences through a softened lens. Memories become warmer, simpler, almost sacred.. The rough edges fade and complications dissolve. We may find ourselves thinking, “everything was just better back then.” That’s how my sleepless nights brought back the pool scene—edited, glowing, flawless.
Interestingly, this same bias can also work in reverse. In moments of excitement or confidence, we may reframe painful past experiences as essential steps in our personal growth. Hardships are no longer just painful; they become necessary, even meant to be. But here lies another illusion.
Our brain, ever in love with shortcuts, wraps these reinterpretations in another layer of distortion: hindsight bias.⁵ It convinces us that we "knew it all along," or that we had more control than we actually did. In reality, we’re projecting our present understanding onto the past. We look back with knowledge and maturity we didn’t yet possess, and in doing so, we retell the story not as it happened, but as it now seems to make sense.
This cognitive heuristic, while comforting, can be dangerous. It gives us a false sense of clarity and mastery, which often leads us to underestimate the complexity of past decisions, and worse, to repeat the same mistakes, believing we’ve already learned our lesson.⁶
When the Brain Zooms in on What Hurts
While rosy retrospection nudges us to romanticize the past, and hindsight bias tricks us into believing we could have predicted it, negativity bias causes us to focus more on unpleasant experiences, giving them extra weight.⁷
My memory of those sunny pool days is a good example. If, instead of the laughter, what surfaced first were the arguments with friends or the moments I had to leave the game to take care of my sister, the entire image of carefree joy might have crumbled. The brain often works this way: it flags signs of discomfort, pain, or frustration as more urgent and more important than the positive details surrounding them.
But then, why do some memories become soaked in warmth and nostalgia, while others fall prey to negativity? Part of the answer lies in the emotional filter we use when retrieving them. This effect, known as mood-congruent memory, reflects the way current emotional states bias which version of the past we retrieve. In this sense, memory is less a fixed record of what happened and more a reflection of what matters to us now.8 If we access a memory while we’re anxious or doubtful, our brain may prioritize signs of conflict or failure. If we’re feeling safe or longing for comfort, it might highlight the gentler details.
Some see this as a survival mechanism. Historically, paying more attention to risks and threats has been essential in keeping us safe. But for many of us, these effects can be exacerbated and lead to disruptive distortions. Sometimes, even a small moment of discomfort within an otherwise positive experience can color the entire memory.
Combined with the availability heuristic—our mental shortcut for judging how common something is by how easily we can recall examples—this tendency can make negative memories feel disproportionately frequent or significant.⁹ That steals energy, peace, and presence from the moment you are living right now.
The Price of Remembering Wrong
It’s clear, biases shape how we remember the past and impact how we deal with the present… But why does it matter?
On one side, there is underthinking. A kind of autopilot mode. Rosy retrospection makes us romanticize the past so intensely that we forget its complexity, the pain, the doubts, the messiness. Everything seems warmer, simpler, and more meaningful than it really was. Meanwhile, hindsight bias makes you underestimate the challenges you went through. It makes you believe everything was always predictable, that problems solved themselves, and that there is nothing left to worry about. It creates this false sense of control, as if life is already sorted out.
Sometimes the brain chooses not to think too much simply to avoid suffering. It works like a mental protection filter. Instead of processing uncomfortable memories or difficult emotions, it builds a shortcut that says, “If I don’t think about it, it can’t affect me.” But it does not really work that way. The problem does not go away. It just gets pushed somewhere to the back of your mind.
On the other side comes overthinking. And that is when availability takes the wheel. If something bad happened, the mind starts believing it could happen again at any moment. This anticipation can create harmful patterns of thinking that aren’t grounded in reality. It feels as if you stay on high alert and obsessively think through every possible worst-case scenario, you will somehow prevent it from happening. The result is a loop of fear, anxiety, and mental exhaustion.
In the end, both underthinking and overthinking are ways the brain deals with discomfort. Neither of them is sustainable. One pretends the problem doesn’t exist. The other convinces you that problems are lurking at every corner.
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How to Escape the Memory Trap
Given all this, the natural question is: how do we break this cycle? How do we avoid falling into the autopilot of underthinking or the mental trap of overthinking?
There is a way out. And it comes from a combination of cognitive and emotional strategies.
The first antidote tackles underthinking. And it starts with being honest about one simple truth: the past was not linear. There was no ready-made script. You did not really know what you were doing. The meaning you give to those events today was built later, with maturity, with experience, with everything you have learned since then. That is why the key here is to practice counterfactual thinking. Ask yourself:
- What was I feeling at that time?
- What options did I actually see back then?
- What resources did I have emotionally and mentally in that context?
When you answer these questions, you break the illusion of control. More than that, you start looking at your past with more compassion and less judgment.
Next, a remedy for overthinking. And this one is very concrete: work with the evidence. Ask yourself:
- How many times did this really happen?
- Is this a rule or an exception?
- Am I stuck in the fear of a memory or in the actual facts?
And more than that, actively practice reconceptualization. If this happened, what did I learn? What no longer repeats itself? What do I do differently now? That way, pain stops being a constant warning and simply becomes a page already read, no longer the whole book.
Finally, there is one last lesson that applies to all of this: The fact that our memories change does not mean they were not real. It means they have lived different versions of themselves across time, shaped by who we were, who we are, and who we are becoming.
That memory of the endless summer of the pool of laughter was real. It is still real. But it has also been retouched, reframed, and seen through countless lenses. And that is not a flaw. That is what makes it beautiful.
In the end, our Patronus is not a lie—it’s a version of truth our present self can live with. Memory doesn’t preserve the past; it keeps rewriting it so we can keep going.
