I've been chasing a "white whale" bacon / egg / cheddar on grilled Texas toast sandwich I made 20-ish years ago that I've never been able to replicate. I didn't keep track of the particular bacon or cheddar I used, and I don't recall if the eggs were the farm co-op eggs we used to get or plain old grocery eggs. I should have taken notes but didn't.
It's probably a silly thing to do, but I keep fairly meticulous notes about food I make now (including weighing-out ingredients on a kitchen scale). I don't want to have another experience like my mythical sandwich.
My wife has a good point about my quest: I can't replicate my hunger level that day. That got me paying attention to how hunger effects food enjoyment. I now make a point of planning my eating ahead of special meals to maximize enjoyment. It's shocking, to me, how much a little hunger makes food better.