One of those phrases that drive me nuts is "think outside the box". A lot of the problem is that people don't bother to *think* "inside the box" (in the usual framework), particularly when it's repeated as a mantra (yesterday I heard someone say it to me three times in ten minutes .... gnnnhaaahhh, makes me stabby).
The problem isn't so much the box, its the lack of thinking.
We have frameworks - ways of thinking about things - for a reason, and we should take advantage of them first. Then, maybe we should consider if the framework is the problem.
You want an illustration of the emptiness of the concept "think outside the box"?
An obvious one is that rarely to people give you strategies for doing so*. Without it, "think outside the box" is pretty useless.
Here's a second one: the people exhorting you to "think outside the box" can't be bothered to think outside their framework for long enough to come up with a less hackneyed and overused phrase, thus illustrating that they are utterly unable to follow their own advice for the few minutes it would take to come up with a more interesting expression.
"Think outside the box" is about as useful and as cliche as that poster of a kitten saying "Hang in there".
*(de Bono does have some exercises/approaches that are sometimes useful, sometimes not -- but he also doesn't say "think outside the box", thankfully)