First, a little backstory--both the illustrious Diana Kingston-Gabai and I watch Battlestar Galactica, which is busily winding its way towards its season finale.
As with rather a lot of things, the ultimate success of the show isn't something we entirely see eye to eye on--she finds its spontaneity to be fresh and exciting and never predictable, I find it to add a lot of energy to the show when they work and a lot of unfocused rubbish when they don't.
One of the cornerstone's of the show's success is that it eschews the notion of random episodes that may or may not move the over-arching plot forward (as the 1970s series did and s/f television as a whole has done for pretty much all of its lifespan) or a tightly-plotted arc wherein every episode serves the function of chapters in a novel (as occasionally experimented with on Babylon 5 and, occasionally, Star Trek) BSG apparently just goes with whatever feels right at the time, even if it doesn't make a terrible amount of sense or require lots of bending over backwards, plot-wise to justify later.
Sometimes it just about works, and it does add a layer of unpredictability and excitement that's more immediate than a more planned-out arc would be. TV Tropes has a name for it, just like they have a name for everything:
The Shocking Swerve.
The Shocking Swerve comes to us, as so many things surprisingly do, from the world of pro wrestling, wherein, in an effort to keep things fresh week in and week out, it becomes necessary to add excitement and unpredictability into things.
Wrestling is pretty simple storytelling when you get down to it--to write it, all one needs to do is provide a sufficiently compelling reason for two people to have a fake fight that other people will pay to see or watch on television.
At a basic level, this is accomplished by dividing your personnel into good guys ("faces") and bad guys ("heels") In the last 15 years or so it's become fashionable to stake out points all along the line--your heroes act a bit like villains and villains are allowed to be not totally irredeemable bullies or cowards or whatever.
This, ultimately was the petri dish from which the Shocking Swerve spawned.
Here's the ideal form of the Shocking Swerve. I will be using the characters from the old NES Pro Wrestling game because I stopped maturing around 1988 or so:
King Slender is mad at his longtime tag team partner, Star Man. Star Man, apparently has been holding him back and King Slender is ready to strike out on his own. They very nearly come to blows multiple times during the course of the show, necessitating the making of a match that will serve as the Main event for the night, which will have Fighter Hayabusa as the Special Guest Referee.
The match begins, but King Slender and Star Man seem to be unwilling to tie up and begin the match. Words are exchanged between the two, perhaps some shoving. King Slender, frustrated, slides out of the ring and grabs a folding chair (folding chairs, despite being the most dangerous things in the pro wrestling universe, are plentifully available around ringside--it has always been so) Slender slides back into the ring, raises the chair above his head, ready to clobber Star Man . . .
. . .and waffles the HELL out of Fighter Hayabusa. Star Man and King Slender both put the boots to Fighter Hayabusa and once he's well and truly out, they embrace and pose in the ring, the clever heels who put one over on everyone. Never mind that neither of them had a feud with Hayabusa at all so their animosity comes from out of nowhere--we've managed to shock the audience.
It might be thrilling, it might even have been awesome, but the "awesome" buzz only lasts as long as it takes to hit the men's room or, if you're lucky, the arena parking lot. Perhaps a little of the blanks can be filled in on subsequent installments of television, but for the sake of a quick shock, you're really punched a hole in your long-term plotting.
So, as you see, the Shocking Swerve is a two-edged sword that breaks as much as it fixes. In other places I've likened the Shocking Swerve to a nitrous booster in an engine--useful for quick bursts of speed, but using it all the time will destroy the engine beyond all repair.
Unfortunately, there are many examples of use
For an example of this in wrestling, I give you World Championship Wrestling. For those of you who find Wikipedia a little dry, here's a snippet from my favourite disaster novel The Death of WCW, which is well worth your time to read, if you stories wherein things with every advantage and expectation of success fails with the vigor and determination that is usually only seen in successes:
"Wrestlers retired forever . . .and then unretired days later. Matches ended when wrestlers who weren't in the original match pinned other wrestlers who also weren't in the match."
WCW, you see, loved the Shocking Swerve and used it ten times an hour . . .in three hour long shows. Imagine if you will the resultant catasto-fuck that ensued. I don't have to--I was watching at the time, and I assure you the authors of this book are being far more charitable about the quality of the programming. I remember it as being so excruciatingly awful that I wanted to injure the people responsible.
So the Shocking Swerve is something I'm not big on, or at least, I'm not big on its overuse. There's a certain fallacy that planning out a long, involved arc that will be the spine of the story that leads you towards its logical conclusion somehow locks you into a certain plan that cannot be deviated from, and really, that's just not the case. It does help to have a vague idea of where you're going when you set out, as it keeps you from getting lost. You'll still be able to make all your pit stops and interesting detours, but you'll be assured of getting there in the end, also.