This week's big episode of "Grey's Anatomy" (but then, aren't they ALL big?) is the much anticipated (but then, aren't they ALL much-anticipated?) "If Then" episode. Meredith starts to wonder what if her life had been different. She re-imagines her alternative universe, where everyone is happy, and her mom is nice to her, and Izzy Stevens never existed. The first 10 minutes were released online over the weekend.