Poor communication skills as plot device

I've grown in awareness when I'm watching or reading something of the prevalence of the unfinished sentence as a major plot device which simply wouldn't work in real life. This was used to horrible effect in the old X-Files, where if Mulder would simply finish a sentence, or add in a single detail when explaining something to Scully, she would have had enough information to actually HELP him sometimes.

Hypothetical example:
Agent 1 and Agent 2 are leaving from Spybase Alpha to infiltrate the underwater lair of Dr Devious.
Agent 1: How are we going to get in?
Agent 2: I'll go first and let you in.
Agent 1: How will you get past them?
Agent 2: I have a plan.

Flash forward - Agent 2 is seriously behind schedule, Agent 1 panics, stumbles into some guards, is taken prisoner, and is being brought before Dr Devious. In a nick of time Agent 2 pops out of a pool of water and saves Agent 1 "didn't I tell you, I can breathe underwater?"

If Agent 2 had just TOLD AGENT 1 his plan was to swim under the whole damn island because he has GILLS, Agent 1 could have sat back and worked with that. But NO. Agent 2 didn't reveal the plan. And it's not like they didn't have a good few hours in the SpyJet, just the two of them, flying to Dr Devious' island. What else did they talk about? American Idol???

This may seem extreme, but for god's sake, it's used on a weekly basis on just about every one of my favorite shows. (And of course in those Maximum Ride books: Anyone: "Max, let me tell you some useful information" Max: "WHATEVER!!!" )

And when they do it, I want to scream because it is just LAZY WRITING. Even well written shows like Fringe are guilty - The cellphone conversation where if they just added ONE MORE SENTENCE to the conversation prior to hanging up, things would turn out differently. Like "I'm at the corner of Dunn and Bradstreet", or "I think that my wound is growing more infected", or "He's acting strangely". Things that I imagine you or I would probably add in.

So writers, and I know there are so many of you reading this, please please please, if you catch yourself withholding information to further the plot, that's ok. But then at least be realistic with how people who HAVE the information would USE that information. In a life threatening or strategic situation, a person sitting on a key bit of info and somehow NOT revealing it during the entire course of a transatlantic flight, or just before a firefight is just absurd.

At least let the person either NOT have an opportunity to be sharing the info (IE - don't have them talking in 90% detail about something but then trailing off "there's more.... but we don't have time"), or let them actually share the info WITH their people, but not US, so we can all be pleasantly surprised by the entire SWAT team crashing through the wall taking out the Vegan Terrorists because the whole group was working with the best possible information.

We as viewers can still be surprised.
And I'll be a lot less frustrated.