Hmm. Anything done well can work. But here are some devices that people use out of laziness. They all do the same thing. They avoid writing great scenes and use lazy shortcuts.

Voiceover: Rather than showing the characters in action, someone speaks over images and explains what they are seeing. The writer is usually too lazy to SHOW you real people doing real and engaging things.

Song playing over people acting: To show the passage of time, movies sometimes show people doing things together -- dancing, walking, eating, etc. -- with some pop-music soundtrack. The idea is to tug at the viewer's emotions ... and to kill 3 1/2 minutes. Listen: 3 1/2/ minutes is an eternity in a great film. You can show a whole scene, with the characters facing difficult challenges and somehow changing in the process. So that 3 1/2 minutes you just spent on a soundtrack is lost to real storytelling.

Writing down the nose: Using bad dialogue to summarize the story and the backstory. Like this:

"Did you have a younger sister? What was her name? Mary?"

"No, Maureen. Yeah, we haven't seen each other in years."

"Home come?"

"Well, she developed this drinking problem and got in a terrible car crash and paralyzed the other driver."

"How horrible. Did she ever get help for her drinking problem?"

"No! And I told her I wouldn't see her till she did..."

"Oh, maybe that's the only thing you can do. Still..."

"Tough love."

"Yeah, I guess..."

Rather than weaving useful information into legitimate scenes, the screenwriter just tells us background information. The problem is, it's not action and it doesn't really show us anything about how characters really behave.