Viewers get some insight into "dark and twisty" Meredith's upbringing, as she spends more time with her cold and demanding mother, who is suffering from Alzheimer's, and her milquetoast father, who didn't fight very hard to have contact with her as a child after her mom kicked him out of their house. It's no wonder Meredith ended up emotionally damaged and unwilling to completely open up to Derek Shepherd (Patrick Dempsey) ... a.k.a. McDreamy. Though the show's title implies that Meredith is the most important character, it's not true. The ensemble cast, which also includes James Pickens Jr. as Dr. Richard Webber (who had a long and complicated affair with Meredith's mother) and Kate Walsh as Derek's ex-wife Addison, is fantastic. And it's difficult to outshine Oh, who has some of this season's funniest and emotional moments as she navigates a relationship with Preston Burke (Isaiah Washington), who is far more romantic and traditional than she is. Though not as compelling as the show's debut season, this third year still packs a strong emotional punch. --Jae-Ha Kim