Say you are in a nice restaurant and, at the table next you, a gentleman lights up the most offensive cigar you ever smelled.
You mention it to the manager and then the manager goes up to the gentleman and says “Sir, I’m going to have to ask you to put out your cigar.” rather than “Sir, please put out your cigar.”
It seems the second statement is the preferred way to say it (e.g. no passive voice, contractions, not wordy).
However, I hear the first statement more often.
Why would you put all those words in front? Does it come out less offensive that way?
I’m sure you suspect the answer: The preferred phrasing is more subservient and less demanding (a role many waiters at fancy restaurants are encouraged to play) even though they mean the same thing.
Sir, I’m going to have to ask you to put out your cigar.
The previous sentence carries a few implications. One might expand it to:
Sir, I would never ask this if it was up to me, but those damn rules they make me follow FORCE ME to ask that you please put out your cigar. I don’t blame you, of course.
That is, it’s implied that the person asking isn’t personally bothered by your cigar; he’s just forced to ask you to stop by company policy.
In a less fancy resturant, one might say:
Sorry, but we don’t allow smoking in here.
This is the same exact idea. “It’s not up to me; it’s company policy, sorry!”
It may seem silly (and it is, in some sense), but it probably does help the customer not feel like an idiot!