Life is short, the art is long
There is an intimidation in knowing you’ll never read all that you want to read and never write all that you want to write. There are nearby dimensions you could know but won’t. "βίος βραχύς, ἡ δὲ τέχνη μακρή," or "Ars longa," vita brevis," or "Life is short, the art is long." That aphorism was originally by Hippocrates about the practice of medicine, but Chaucer extended it in 1380: "The lyf so short, the craft so long to lerne." Those phrases acknowledge the fact, but not the dread or urgency behind it.