"Blue Bloods" fans on Reddit agree that Danny Reagan's best partner was Jackie Curatola, played by Jennifer Esposito. However, Esposito left the show due to chronic illness, which stemmed from a demanding filming schedule. The producers claimed her part-time schedule was incompatible with the show's needs, but Esposito hinted at conflicts between her and the producers. Despite her departure, Esposito continues to pursue a successful acting career. The loss of Esposito's character means no more captivating drama between Jackie and Danny on the show.