This is a question people have to ask themselves in dramas
It's business as usual for most people - except for those dealing with ghosts and mythical creatures and random body swapping
Well naturally we were all connected in our pasts lives. That's how this works!
It doesn't have to be a hidden childhood connection, but let's face it, it probably will be
tried and true way to fall in love, become friends, cause conflict, hide from the bad guys
Also sometimes known as the Enemies to Lovers trope, depending on the story
Usually manifests in the Rich Man, Poor Woman trope. But who's to say the reverse can't happen?
Trying to heal people would be a lot easier if it weren't for all the pesky hospital politics getting in the way
Straight up or fusion, it's fully set in the past. Also includes if the present is just in the beginning/end
A side plot at best - everyone is much more concerned about other things
Come for the underdog story, stay for the takedown of corrupt politicians and corporations!
Either the unsung heroes or the outright villains of the world
Sometimes it's two different worlds; sometimes it's unraveling the mysteries of two simultaneous stories
Prosecuting and defending on behalf of justice! Or, you know, overseeing mergers and contracts and all that jazz