Some tropes are so pervasive that they're like air, normally difficult to notice. Then one day, it suddenly hits you: of course, The Epic! Or Bank Robbery, or Magic Carpet, or what have you. Oddly, nothing comes up on a site search, so you take it to TLP in puzzled disbelief.
But we must have this, you say. It's so obvious! Surely it's here somewhere. I really can't believe that we don't have this yet. Come on, people! It's the True Meaning of Christmas! It's one of The Oldest Ones in the Book, and it's all over the place. And The Great Crash of 2008 had nothing to do with its absence!
How Did We Miss This One!?
The answer's pretty ironic: usually, it was missed because it was so bleeding obvious, common, and/or basic. So nobody thought an entry was needed, or everybody figured it was already here. Or everyone just Failed a Spot Check. (Or, in rare cases, because People Sit on Chairs, and thus not actually a trope.)
DO NOT use this phrase in the trope sections of work pages, or the examples sections of trope pages. If you think of an obvious trope example that has been missed, just add it without drawing attention to it. We won't tell anyone we missed it if you won't.
Important Note: This kind of thing happens in real life all the time, many of the most earth-shattering philosophical ideas of all time are now known as "common sense," mathematically even more so: someone had to actually design the standard punctuation system of mathematical processes. "I think therefore I am?" Not before Descartes, ya didn't.