Many people complain that the speed of light is too low for interstellar travel, and most SF writers invent means of faster than light travel so their characters can flit from star to star in reasonable amounts of time (I did myself in Final Contact because the story didn’t really work otherwise).
But think about that again. The speed of light does mean you’ll never fly to Alpha Centauri and back in a weekend, but it also means you’ll never see bloated interstellar empires telling everyone what to do.
Traditional empires on Earth could handle a few weeks or months delay in communication and travel; even then the military might receive orders for a war that was already over. On that basis, interplanetary empires would be possible, but even expanding to the Oort cloud would be difficult. Power could be devolved from Earth to regional centres, but then you’re already beginning to lose control of your empire.
The nearby stars? Perhaps. Orders might take half a dozen years to reach you, but knowing that a military expedition might appear in a few years or decades if you ignored them could keep you under control.
But beyond that? There will never be a Terran Empire sending orders from Earth to colonists on the far side of the galaxy or loading up the battle fleet with marines ready to enforce the Emperor’s will after travelling for a million years to get there.
The speed of light ensures that the Evil Empire (whoever they may be) will never be able to enslave our descendants. We should be thankful for that.