“I’m sorry I left you up on that ridge, Mike. I’ve always regretted losing your friendship.”

Several years ago, I opened up Facebook to find a friend request and a message from a guy I’d known since fourth grade, but whom I hadn’t seen in years. He apologized profusely and sincerely, clearly having carried guilt over abandoning me, and wanting to make amends. The only thing was, I didn’t know what he was talking about.

A short conversation jogged my memory. On a school camping trip, back when we were sophomores in high school, we had climbed—off-trail—to the top of a ridgeline above our campsite. We’d gone the long way around on the ascent, coming up the shallower slope on the back side, but now the sun was setting and we needed to get back before the evening campfire. We started down the steep face together, but I froze halfway down, overcome with vertigo. He shouted for me to hurry up and went on without me, assuming I’d make it on my own. But I didn’t; three or four other campers ended up guiding me down, inch by inch. I was shaken, and angry with my friend for leaving me, but I got over it.

Over the next few years we remained friends, but as so often happens we drifted apart. He joined the football team; I joined the drama club. We both made other friends. There was never any particular rancor between us, other relationships just became more important. Senior year, we were on the yearbook staff together, and I remember having a few laughs. We lost touch after graduation, but I always remembered him fondly.

This was how I remembered it. But as I discovered when he messaged me, his version of the story was very different: I had been angry and hurt that he abandoned me, and I never forgave him for doing so. Our friendship ended that night, because of his actions, and the regret over the incident changed his life. From then on, he made it a point never to let anyone down, especially if they needed his help.

So, for him, that night on the ridge was a foundational experience. For me it wasn’t even remarkable enough for me to remember it without being reminded. That disparity has been on my mind a lot lately due to an interesting coincidence. Earlier this month, I received an invitation to a Facebook group for alums of the Monterey Gaming System BBS. As it happened, that was the same week that I finally started listening to Serial.

It’s a little strange to think about these days when social networking sites are so central to most people’s daily lives, but back in the pre-Internet days the closest thing was the local bulletin-board system, or BBS. Monterey Gaming System (or, as it was known to its regulars, “MGS”) was the largest of the local BBSes back in the area where I grew up. Boasting dozens of dial-up lines and an active user base in the hundreds, the MGS chat rooms were the place to be for the computer nerd of the early 90’s Monterey Peninsula.

I was introduced to MGS around 1990 or ’91 by the friend from the story above, and for about three years it was my main social outlet. Most of my good memories from the first two years of high school—which were generally terrible for me—come from the time I spent in those chat rooms or hanging out at the local bowling alley during one of the “get-togethers.” My first steps toward understanding myself as an individual came during experiences I had with that group. I even met my first girlfriend there. In retrospect, I’m not sure why I stopped going, though by the time I left for college it was mostly a thing of the past.

The thing that has been the most striking to me about reconnecting with the group after twenty years is how poor my own memory of that time is. In the past two weeks, dozens of threads have popped up in the Facebook group, people sharing stories about the old days. And it’s been shocking to me how few have sounded even a little bit familiar to me. With just a few exceptions, I can’t even remember people’s names. Somehow, despite this being a formative period in my life that I think about regularly, the people and places have mostly slipped my mind. The question that I keep coming back to is: why don’t I remember this better?

And this brings me to Serial, the wildly popular spin-off podcast of This American Life. For those of you who haven’t heard of it, Serial debuted last year with a twelve-episode arc examining the 1999 murder of Hae Min Lee, an 18-year-old high school student from Baltimore. There’s a lot covered in those twelve episodes, and the series is well worth a listen if you haven’t already done so, but what intrigued me the most was the way in which the people involved in the case remember the people and events so differently. The series is largely an attempt to understand whether the man who was convicted of the murder—Lee’s ex-boyfriend Adnan Syed—was guilty or innocent, but depending on which present-day interview you give the most weight, Syed is either a golden boy or a manipulative liar. And the same discrepancies pop up in people’s descriptions of nearly every facet of the case. In some ways, this isn’t so surprising given that the interviews happened some fifteen years after Lee’s murder, but the huge variations in how people remember Syed, Lee, and what happened that day is striking. What’s more, even the contemporary accounts vary wildly, and not all of it can be explained by the possibility that some people are lying.

Being the sort of introspective person I am, I have a definite picture of who I am now, and who I was at many points in my past. This sense of myself, of awareness and understanding—in many ways this is fundamental to my experience of life. I know that my identity and my ways of being have changed over the years, but even that process is something that I have thought of as comprehensible. Or at least known. More and more, though, I’m coming to the realization that that understanding is flawed.

And that stands even though my conception of my past has changed over time. Leaving high school, I saw myself at 14 as a victim, pushed around and bullied by people stronger and cooler than I was. Ten years later, I looked back with what I thought was clarity and saw the self-absorption, the arrogance and cruelty I displayed at that age, and I admitted that what I endured was at least partially my own fault. Another ten years have gone by, and neither story seems to stick on its own.

Who was I when I knew the people I’ve been reconnecting with? I can tell you about the length of my hair (long), the music I listened to (mostly metal), and the awful poetry I wrote (self-indulgent, but not atypically so for someone going through puberty). I can chuckle about how seriously I took myself, how simple my views of the world were. But is that right? Was I so silly then? Am I so much more advanced now?

What does it mean for my friend if a lifelong regret—one that influenced all of his subsequent relationships—is based on something that didn’t happen? What does it mean for my understanding of myself if it did? Is identity nothing more than a story we tell ourselves in the present? And can we ever really know what our own story really was?

Memory is such a tricky thing. It’s so susceptible to being influenced by our present state of mind, and not just in color but in the details, which can disappear or even change as the story we want or need changes. In Serial, Koenig often butts up against the fact that the narrative she gets changes based on who’s telling it, or that people have no memory of the day at all. It’s a frequent refrain that we don’t pay attention to what happens on a normal day; it just doesn’t stick. But it’s hard to know at the time which days end up being normal and which become important, and how, and to whom. And if life is mostly a sequence of normal days, what are the implications for our conception of that life if we can’t remember those days?

As I’m writing this post, my son and older daughter are in the other room playing. I don’t know exactly what they’re doing, what’s causing the laughter and shrieks. I can’t help but wonder what they will take away from this time, what they will remember in twenty years and what they will forget, and how that will differ from what I remember and forget. Time will tell, I suppose.