This is based on opinion. Please don't list it on a work's trope example list.
Tearjerker / General Hospital
The Thanksgiving episode after Edward passed away, when it shows him walking into the light with Lila.
The death of BJ and Maxie receiving her heart. Tony laying his head on Maxie's chest, listening to BJ's heart, and Felicia breaking down when she realizes whose heart Maxie is receiving.
Called back a decade later with Tony's own death, heroically saving many lives from the epidemic that would take his. After saying goodbye to his loved ones, he begins fading fast and with his last breath, excitedly calls out for BJ as if he sees her.
Alan's death. Especially since he and Jason were finally beginning to thaw their years of estrangement. Jason took his death very hard and confided to Monica that he regretted all the years he pushed him away.
The Death of Stone.
Georgie's death, especially Maxie's reaction. Spinelli's reaction to it also deserves mention, because at that point he was Georgie's closest friend, and vise versa. Most heartbreaking is that he found Georgie's body, and tried to wake her up and begged her to take a breath before completely losing it.
Carly's grief over Michael's perceived death. After being in complete denial about it she goes into hysterics, and Sonny tries to calm her down so they can both be calm enough to tell Morgan what happened. It feels like a punch in the gut when Carly sobs, "I don't want to live in a world that would take my child away from me!"
Spinelli finding out from his girlfriend Ellie that Maxie's didn't give birth to Dante and Lulu's baby as a surrogate, but her own and that Spinelli is the father.
Karen breaking up with Jagger after remembering that she'd been molested as a child, believing that she wasn't good enough for him. After months of a downward spiral due to these same beliefs—drug use, working as a stripper, nearly flunking out of college—she finally breaks down and tells him what happened to her. He breaks down too, tearfully asking, "Why didn't you tell me?" and assuring her that he never stopped loving her.