'Tell It To the Frogs' (Season 1, Episode 3)
After the pilot established the show's main theme as "man against nature" (with zombies as "nature”), series creator Frank Darabont spent the rest of the season making it all about "man against man." Rick finally found more survivors, and then quickly discovered that he was going to have more trouble getting along with humans than he'd had dispatching walkers. In "Tell It To the Frogs," the lawman is reunited with his wife, Lori (Sarah Wayne Callies), and son, Carl — and his best friend Shane, who's been sleeping with Rick's spouse in his absence — in a camp populated by a wife-beater and a pair of racist redneck brothers. Tension builds throughout the episode, as Shane stews back at camp, while one of the angry hicks, Daryl (played by the inimitable Norman Reedus), joins Rick on a mission back into Atlanta to rescue his peckerwood sibling. When Shane and Daryl finally explode into violence, it's because they've been driven to it by other people — not by zombies.