I would like to reinforce that scripting can be beneficial if player agency isn't squelched too badly, or ideally, at all. Like that couple fighting at the market - there's a story there, but are you going to get involved? What could the PC's interaction with that plot mean? The plot continues despite the PCs - it was happening before they witnessed it and it'll happen after.
If I have 2-3 of these per session and run them in the background (yay, GM story time!) and keep track of them, then I have the appearance of a living world.
YEAH! Now somebody is talking my language. I often make up locations, NPCs and storylines that lend a sense of realism and presence to the area we are gaming in even if there is little or no chance the PCs will go there. If I do spend the time to work out an encounter, its certainly not going to be uprooted and moved to some other world. Typically it has tangibles that belong to that specific environment and not likely to fit without considerable modification elsewhere anyway.
Our game is currently on Cona and I have pages on a number of interesting locations on the planet and specifically the region around the city the players are currently in. There is no real reason for them to go to any of them but if they do, well there are there. And if they don't, well for me it gives the planet substance, the environment depth.. I can imagine there is a leaving breathing world out there behind the confines of the PC's storyline.
The bleak volcanic region the Arcona travel to perform the Karam’t shu meditation in order to commune with the spirits of their passed relatives. (and which is also incidently quite strong in the Force, the center of the old Arcona Jedi and possible location for their secret and now lost temple)
The mining facility dug into the cliff face above an ancient Arcona nest. The two cultures co exist peacefully as long as the mining is controlled and not allowed to interfere. A recent discovery of rare ore however threatens to expand the mining operation and destroy the decades old balance between the two peoples.
The pair of massive Orbital Catapults that provide delivery of local payloads to waiting barges in orbit. The cost is far less than arranging for on site pick up and utilizes a planetary carrier serving the entire region. Recently however the carrier has escalated his fee in the face of established contracts and threatened strike if his demands aren't met. Attempts to attract another carrier have resulted in threats of Union action against strike breakers and even violence. The planetary governor has sent in an arbitrator to try and settle the dispute but so far there has been no progress. In the mean time, shipments to more than one refinery, subsidized by the Empire, have complained their imports are delayed and production behind schedule. The empire could become involved at any moment.
These are the kinds of details I populated the area around the Players when they arrived on Cona. They may have an impact on play, and they may not, but they are there along with several others, and serve to make Cona a real location and not a backdrop for the player's actions only.