system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do random little moments that I haven't though about for years, pop into my head at seemingly random moments?

Like, not even embarrassing moments. I'll be sitting at my desk, and suddenly remember being in a carpark with my friend 15 years ago..
gpt
You know how you can often see or smell something, and it triggers an easily recalled memory associated with it? The easiest way to understand involuntary memory recall is that its exactly the same as any other memory. It is triggered by something.

The difference is you are not aware of what the trigger is. Unlike thingsi n the environment triggering memories, with this its other memories triggering the memories. Usually a chain of memories set off by some mundane process, in just the right way so as to trigger recall. But because you don't know what the specific thoughts are that triggered it, it seems random.