Sarah Palin demonstrated last night one sort of trouble you can run into when you use cliches.
She said this: "Nuclear [or 'nukyular'] weaponry, of course, would be the be-all, end-all of just too many people and too many parts of our planet."
"Be-all and end-all" means "the most important thing." There might be some lunatics for whom nuclear weaponry would be the ultimate possession. In fact, we believe those people are right now lubricating the axis of evil with rendered baby fat, or something along those lines.
But we're guessing Sarah Palin thinks the expression means something else--perhaps "the end"?
When our brains go on autopilot and insert entire phrases that sound familiar and vaguely right, we should beware. Unless we really know what the whole phrase means, we shouldn't use it. It reminds us of that scene in "The Little Mermaid," where Ariel combed her hair with a fork. Disney meant that to be funny. Sarah Palin probably wasn't playing nukes for laughs.
In any case, it's the mark of a fine and creative mind that can dispense altogether with second-hand phrases.