Especially during the early stages of a product definition ...
For example: There is a classic "Math Games" problem that goes something like this.
Take a piece of paper and draw 9 dots arranged like this:
x x x
x x x
x x x
Then ask someone what is the minimum number of straight lines that are needed to connect the dots assuming that you can not lift the pen/pencil when connecting the dots.
Sure it is pretty easy to do it with four ... but with only 1 ??
How can that be? Simple, use a paint brush, and do one wide line.
Okay: State the obvious. Here's the pencil, standard #2.
Answer: Still 1.
How: Use a pen knife, remove all the wood and get back to a "wide" stroking device.
Okay: Restate the obvious: Use only the "correct" width.
Answer: Still 1.
Why:? You never said I couldn't cut the paper, line the dots up in a straight line and then draw a single line.
Okay ... you get the picture. What is "intuitively obvious" to you may not be to someone else who is trying to be obtuse or just came to the puzzle with their own ideas/mindset.
More Examples:
"You mean the CommSvr HAS to be on the same machine as MS Exchange Server?"
"You mean the CommSvr HAS to be able to run on a machine separate from the MS Exchange Server?"