Chris Bateman on Grinding

Grind is often singled out for criticism, but this is because when players notice they are grinding, they have already lost interest in the activity they are being asked to perform. Pragmatically, those games which rely on reward schedules to structure their play can maintain interest for radically greater lengths of time than those that do not — and provided what the player is asked to do does retain some interest, the grind is precisely what maintains the player’s interest. While some game designers try to develop mechanics which avoid the grind, games that make use of grinding are becoming increasingly significant in the commercial market for digital games.

— Gamasutra – Features – What Is A Game? An Excerpt From Imaginary Games