If you're looking to instruct, guide or otherwise influence another person's thinking linquistically you might adopt a particular strategy with the intent of making your communication effective in yielding your desired outcome (begin with the end in mind).
Your strategy may include the use of very clear, specific instructions with little or no ambiguity. You may give these instructions in a very direct even authoritarian manner so that the person you're communicating with understands exactly what your expectations are.
This type of strategy can be perfectly useful in certain sets of circumstances. In other circumstances this type of strategy can actually lead to the protraction and frustration of the entire process and ultimately stop you from getting your desired outcome.
An example of a situation in which a direct, authoritarian strategy would be applicable and useful is in programming a computer. Humans program computers using certain specific computer languages developed expressly for the task in hand. These languages are unambiguous in nature and the computer follows to the letter the instructions given to it without question as it has no critical faculty.
Humans, however, are far more sophisticated than computers in their powers of discernment and analysis. Humans can think for themselves and can analyse almost microscopically any communication offered to them. Humans do possess a highly developed critical faculty.
In order to process a linguistic communication from another person we have to use our own model of the world to apply meaning to the words and phrases that they use.
We also use our own model of the world to answer questions such as '...how does this communication relate to ME?' and '...how do I feel about this communication?'.
Our critical faculty facilitates us in analysing the communication further still to think about, for example, the potential effects of acting on the instructions given to us.
Ultimately, unlike a computer, we can choose to respond to the communication or any part of it in a myriad different ways. And some people think computers are tricky!
If the communication or any part of it is not congruent with our model of the world we are likely to disagree with or reject or otherwise resist that communication / suggestion / plea / instruction / order / demand.*
*I've purposely offered some interchangeable words in the above paragraph to describe some common types of linguistic communication - words which often carry varying degrees of emotional charge.
Imagine finding yourself on the receiving end of a plea. Then imagine being on the receiving end of an order or a demand.
Compare and contrast those thoughts and your reactions to them - are they different? Would you react differently to a sincere, heartfelt plea than you would to a forcefully delivered demand?
Are the words '...it would be ever so useful if you wouldn't mind...' more or less appealing than the words '...Do it now and do it like I told you...'?
It is fairly common to find that people are more resistant to being told what to do than they are to being asked to do something, or to being offered a suggestion which they can freely choose to accept or reject.