Every planet's population grows up thinking it's alone in the universe. It's only natural. When it seriously considers the possibility of life on other worlds, it's usually manifested in fear of invasion. Certainly nothing as mundane as the kind of rivalry Naboo and Alderaan experienced between the families of Palpatine and Organa.
Yet that's exactly what happened. They just didn't like each other. Everything one wanted, the other seemed to want, too. And it became ugly.
When Palpatine became ruler of the Galactic Empire, he took it as an opportunity to finally put an end to the feud. Bail Organa had recently adopted a baby girl, lineage unknown, to most people. But Palpatine knew it was the daughter of his pupil, Anakin Skywalker. He didn't particularly care about Anakin's offspring. He believed Anakin himself was the answer to his dream of extending his influence well past his own life. Unlike the rest of his family, Palpatine never had any children of his own. Bail would have been the last of his family, too. Arguably he agreed to take custody of Anakin's child as one last strike against his rival.
In the years that followed, Bail rose the girl as his own, and she thrived as a member of the Organa family, taking up all of his causes, including the feud with Palpatine. Such was the reason she proved to be such a nuisance to the Empire, working against her father's old enemy in every way possible.
Until the day Palpatine ordered the destruction of Alderaan. It was the last thing anyone expected him to do, but in hindsight it was the only outcome possible in his development of the ultimate weapon, the Death Star. The Empire framed Alderaan's annihilation in strictly procedural terms. "Used as an example." "Random selection." But everyone knew exactly why he'd done it.
Bail's adoptive daughter, the last of the Organas, threw herself into the Rebel cause like never before. She stopped trying to hide her support. She found new allies capable of making the boldest decisions, including her own brother. Their reunion was unexpected. He wasn't an Organa, but he shared her same yearning for something more, something better than the pettiness that they had separately known all their lives, the futures that were stolen from them. For her brother, Bail's daughter suspected this had been a change for the better. For her, only heartbreak. Maybe that's why she fell in love with the rogue who would never have found her father's approval had they met.
Or maybe they did. Maybe Bail had engineered, in some peculiar way, his daughter's whole future. Maybe he'd had the foresight his rival had bragged about for years, but never seemed to benefit from, just a lot of manipulations that worked. For a time. But all plans have conclusions. Palpatine's had already been revealed. Soon it would be time to see where the Organas' plans had led, where their feud ended, finally, after far too long.
No one expects aliens to become so mundane. But even the mundane can be spectacular. And end as mundane all the same. Some who end up in this predicament understand that. Some never will.