Recently someone posted about how the ubiquity of cell phones has neutered movie plotlines dependent on lack of communication for dramatic suspense (if someone knows which post I'm referring to, let me know; for the life of me I can't remember where I saw it). For example, Romeo and Juliet would've never ended tragically if the two of them could have texted each other rather than having a messenger try to deliver the news of the faked death ("Drnking drug to fake death for 2 and 40 hrs. Not rlly dead! Meet @CapuletCrypt? <3<3<3 -J")
So screenwriters depend on poor cell phone reception or destroyed cell phones to try and extend the useful life of communication barriers as a plot device.
The plot device that bothers me the most is the use of old-school answering machines to incite conflict. Every time a character comes home with a loved one and then presses play on one of those old-school answering machines, unwittingly playing a suspicious or incriminating message out loud before they can hit the stop button, I picture a lazy screenwriter at the laptop thinking of how to squeeze a plot turn into one page of script. I barely know anybody who still has a landline, let alone one of those answering machines. Mobile phone voicemail just isn't as convenient for a screenwriter, though, so the answering machine lives on.