12. Mayim Bialik: Then
When fans first met Bialik as Amy Fowler, most looked at the screen and uttered the word “Blossom.” For five years in the 1990s, Bialik was famous for playing the title role in the series Blossom. She’s since earned her Ph.D. for real, making her the only legit Ph.D. on TBBT. Amy showed up on the last episode of the third season, where she and Sheldon met on a date. She seemed perfect for Sheldon, a neurobiologist with as many rules as Sheldon, but their romance took a detour.