That brilliant thing you were thinking yesterday... that idea that was really clever and that tickled you for a moment when it popped into your head? That thought you can't remember anymore for the life of you? Forget it.
Yes, the one you really meant to write down but you were too busy at the time to stop to grab a pen. Stop fretting about it. Let it stay forgotten.
It wasn't really all that brilliant. It just seems that way because you can't recall it today.
Separated from you by time and space and an irritating inability to summon it back to conscious thought, it has now taken on an importance and appeal far above the value it really possessed. In fact, the amount of time you're wasting trying to remember it is hurting you in the present time. Your productivity is lowered. You're irritable and distracted. People are noticing that you're off somewhere else. While you're on freeze-frame, you're missing new things—probably more important ones—happening all around you.
The yearning to have that thought back is strong, but let go. There's a reason you can't recall it anymore. It wasn't really that brilliant. Yes it tickled you; made you laugh; gave you pause. But it didn't leave any deep, lasting impression on you that withstood even a day's passing. It was novel, not substantial.
Your mind has done you a favour. Like the rest of the memories you don't need to possess in order to be a functional, successful person, it wiped that thought away. It's in some cognitive landfill now, along with the names of people you met once, television shows you paused at for a few minutes while the commercial was on, and restaurants where you never looked up at the sign on the way in. Or on the way out. Transitory value.
This idea was different? It would have changed the world? Well no... but perhaps it would at least have impressed other people with its quirky, creative, "I wish I'd though of that" insight, or its uncommonly common sense wisdom?
In the harsh light of day today you would see that idea anew, and realize why you'd forgotten it. You'd understand that it only seemed brilliant because you were overtired from a long day, stressed from an awful week... in some delicate, impressionable, uncharacteristic state of mind. Hungry perhaps. But there was no thesis there. No novel. No poem or song lyric. Maybe even not worth a tweet, let alone a blog post.
I still get cravings to have those ideas back. I have to remind myself that what makes it most valuable, most appealing, most addictive to obsess about... is the fact that I don't have it. It's our fundamental nature to want what we don't have.
People waste too much of their time—or even ruin their lives (and the lives of those around them)—in the constant drive to possess what they don't have. Sex, power, prestige, material wealth.
Later when they realize that the thing they absolutely needed to buy was only used a short while after being unboxed... they might understand (or, obsess about the new version). Meanwhile, others elsewhere also have the same thing, still in the box, still in the bag it came home from, sitting in the corner of the room they're in. The value was in the acquisition.
In our present relationships we obsess about the unknown, imagining that things are better somewhere else with some other person; some other company. We leave and discover that some things are better now, and some were better where we used to be.
Find happiness in the present moment, knowing what you know, having what you have, being where you are. And forget about everything else.