Brian, Jim and Tom talk about grind. Grind is eventually defined as work, that isn't fun, that must be done in a game reach an objective, gain an item, or an achievement.
Some may look fondly (in retrospect) on past labors that led to high achievement in a game - but often we look back at time we spend grinding and wish we had done something different.
Grind doesn't always have to be a bad thing. It's sometimes nice to be able to kill time with a game -- just like junk television. Persistent/MMO games also allow you to upgrade your character status while you do this.
Links to referenced items:
Carrot-Stick Forum Article, World of Warcraft, Final Fantasy, Halo Skulls, Braid Stars, Banjo-Kazooie, Super Mario, Beyond Skill - Tobolds, Sonic, Left 4 Dead, Angband, Akimbo Assassin Achievement, World of Tanks, Workification, Runecloth, Winterspring Furbolgs, Chess, Starcraft, Counterstrike, Borderlands, Torchlight, Angry Birds, Comfort Grind, Jetpack Joyride, Call of Duty, Captured Firefly, Captuar - Final Fantasy 3, Dawn of War, God of War, Turtling, Diablo 3, Civilization, Grand Theft Auto 3, Pigeon, BFG, Morrowind, Umbra, Half Life 2.