MTV’s The Hills was once an essential viewing, and fans tuned in to see Heidi Montag and Lauren Conrad—whose friendship once defined the show—until a nasty rumor draws their relationship to a bitter end. Publicly, things remain awkward between them. The feud kicked off at the premiere of The Hills Season 3, when Conrad officially ended her long-standing friendship with Montag, suspecting that she and Spencer Pratt were spreading cruel rumors abo…