tl;dr: Great art has "thickness"—it rewards sustained attention by revealing more layers (discarded approaches, deliberate choices, recurring motifs, real costs paid by the creator), unlike "slop" that evaporates under scrutiny. The author argues English teachers failed to explain that literature is like a cave requiring effort to explore, and warns that AI-generated content and the poptimist erosion of quality distinctions leave us defenseless against thin, mass-produced work. The hard part of making something—the thickening—is the only part worth doing, and it can't be automated.