The "sob stories" aren't solely down to the contestant but really more about the story the producers want for them.
Fleur's story was that she was doing it for her Dad (who died just before lockdowns started in 2020), so they kept talking about it. One of the first things Claudia said to her after her showdance was "Your Dad would be so proud".
Will had a similar story, plus Northern Lad.
Molly didn't really have anything until she ended up in the bottom two so many times, so that became her Thing, despite Fleur being in the same number of dance offs.
Helen's was finding confidence again, though I agree with everyone who said she was always confident. But that was their code for Jilted Woman Living Her Best Life.
Anyway. I'd like the producers to remember that it should be a lovely, warm, lighthearted show and they should leave all the Sad Stuff for the X-Factor.