The film and television tropes discourse is usually centers around how little value (other than unintentional lulz) they add to the films and shows where they are utilized. But this is not always true. Sometimes they are quite helpful to both characters and the audience. Tropes often serve as visual shortcuts enabling filmmakers to get to the unremarkable ending as efficiently as possible. And who doesn’t love a shortcut?
1. The Exposition Hallway Walk
A staple of action and disaster films, the Exposition Hallway Walk involves assembling a collection of who’s that actors around a main character and having everyone stride purposefully down a badly lit corridor as the central conflict is presented to both the main character and audience (usually in rushed tones). In some cases another minor character will race to catch up with the procession in order to add a bit of character or situational back story and is often observed carrying a folder stuffed haphazardly with important papers.
Why it’s useful:Time is of the essence in action or disaster films; there is nothing more vital to success than ensuring that key players are all up to speed.
2. Plot Development is Just a Phone Call Away
No matter how inconvenient it might be, people always answer their phones in movies – unless they’re having sex or being brutally murdered. It’s a good thing too, since each phone call has the potential for information that will forward the plot! So next time you hesitate before answering your phone; don’t. It could be Bruce Willis alerting you that terrorists have seized the Nakatomi Building.
why it’s useful: people might ignore letters, rocks tossed at windows or messages scrawled in blood on a mirror, but rarely do they ignore phones.
3. One More Time for the Cheap Seats
When dealing with convoluted plots, scientific jargon or a really skeptical minor character, repetition, clarification and talking in ALL CAPS is extremely helpful. If the plot has gotten away from the characters, their best bet is to pause, take a deep breath, assemble some who’s that actors and take another hallway exposition stroll. If this science is really important, it will need to be explained in un-sciencey language or perhaps depicted in a series of quick sketches. For skeptics, however, you might just have to shove their face into a wall or extremely close to a recently departed co-star whose bullet riddled body ought to provide enough solid evidence the matter is to be taken seriously.
why its useful: sometimes even the audience can be confused, clueless or unconvinced. 
4. The Guest Star DID IT
As often discussed around these parts, the guest star is usually the killer. This doesn’t mean there won’t be room for plot twists, turns or reversals of fortunes. It just means the writers were lazy or really liked the idea of Matthew Modine subverting his nice guy image by playing a serial killer.
why it’s useful: Sometimes you just can’t be arsed to sit through an entire episode of Law & Order: SVU
5. Unlocked Offices Are for Plot Twists and Passwords
Regardless of how classified the information or fancy the building, offices are rarely locked. In the rare instances they are locked, there’s always a kindly cleaning person who is more than happy to unlock the door. Though if there’s no cleaning person available you can always just shoot off the lock.
Why it’s useful: You’re gonna need those files, passwords or ledgers depicting cash bribes to make it to the end credit crawl alive.
