So, recently there was a moment when I was writing Twin Stars when I had both of my leads (who are living parallel but seperate lives in the story) in transit and in a position to cross paths. You know, the sort of scene you get when two characters are both in an airport and they walk past each other without knowing that the person they just walked past is someone their destiny is tied to. That sort of thing.
So I had the chance to have my leads have that sort of encounter, but I purposely chose not to. Why? Well, part of the reason was it wouldn’t have added anything to the story (which is reason alone enough not to do it), but there was another reason- to do so would have made the universe I’m building seem that much smaller.
I’ll give you another example from a movie series I imagine most people reading this have seen- Star Wars. Now originally Lucas presented the setting of Star Wars as an epic place and he did it with some subtle cues that really worked (hint- How many languages does C3PO speak?) and made the whole place really come alive despite actually only having a few locations in the actual first produced film. That was cool and good, and then he did the second film Empire Strikes Back where we learned Vader is Luke’s father- okay, a real co-incidence, but we’ll accept it as fate, right? Then he did Return of the Jedi where Leia is revealed to be Luke’s sister and Vader’s daughter- hold on? How big is this galaxy again? (I’ll stop there, but coming back to C3PO we find out later that Vader built him as a child, making the Galaxy even smaller.)
My point is- the more connections and co-incidences you have between your characters in a setting, the smaller the setting becomes. If the same six people keep running into each other for no reason other than co-incidence then how big does your setting seem? If they’re chasing each other that’s one thing, but if every time they go to a different Starbucks to get coffee that other guy is there then at some point the audience is going to wonder how many Starbucks there really are.
This I think is one of the reasons why a show like Doctor Who or Star Trek worked well in creating a big galaxy- they were meeting new people and going to new places every week- the place seemed huge and got bigger. But, if you do the reverse (say Doctor Who spent every second episode in Cardiff for no particular reason) suddenly the galaxy seems to be shrinking in on itself. Or if a show has the same villains showing up week after week- is there nobody else out there doing evil? Again, if there’s a reason for this within the story then it’s fine, but there’s going to be consequences and the writers need to be aware of them.
You can fight this to some degree by going out of the way to let your audience know how big the setting is in subtle ways (et tu 3PO?) as the little things often do a better job of showing the scope of the setting than outright saying it. (It takes HOW long to get from A to B? That’s a long time!) But the best remedy to keeping your setting from turning into a fishbowl is limiting co-incidence as much as possible. Which you should be doing anyways since things not happening for a reason in a story is bad writing anyways!