Showing deferece addresses the listener’s want of freedom from impositions and interruptions. It assumes the listener is socially distant.
The following list of deference politeness strategies is not intended as a prescription on how to behave, but as a clarification of implicit messages behind typical people’s utterances.
1. Conventionally indirect speech.
This strategy delivers an explicit, “on record” message, while using indirect syntax that conveys the speaker’s desire to avoid an on-record imposition.
Can you pass the salt?
The imperative “pass the salt” is phrased as a question that inquires whether the preconditions for making such a request are in place. Preconditions in this case would be: the listener’s capability of passing the salt (
Can you reach the salt?), the availability of salt (
Is there salt?), the speaker’s sincerity of wanting the salt (
I would really like some salt), etc. The speaker avoids presupposing that those preconditions are in place and thus avoids making a demand.
Can you pass the salt, please? The word “please” marks the sentence as a conventional indirect request which cannot possibly be taken literally as a question.
Can you play Beethoven’s Moonlight Sonata? This could be either a literal question or a request. The true meaning cannot be determined by the grammatical structure of the sentence, but by the context. If there is a piano in the room, it is more likely to be a request.
Can you please play Beethoven’s Moonlight Sonata? Here, any doubt is removed as for this being a request.
2. Avoid assumptions.
Don’t assume you know the addressee’s wants, beliefs, “and what is relevant or interesting or worthy of his attention”.  Don’t assume he is able or willing to do what you want.
You could perhaps play Moonlight Sonata.
Could you possibly play Moonlight Sonata, please?
A speaker can use hedges in order to mitigate or weaken the certainty of a statement that is potentially face threatening. Hedges can be categorized according to the Gricean Cooperative Principle which is being opted out of:
I may be wrong, but …,
I probably don’t need to tell you
this, but …
This may not be relevant, but …,
by the way …,
I’m not sure if this is clear, but …,
I don’t know if this makes sense, but …
Hedges can also be conveyed with body language and prosody (the rhythm, stress, and intonation of speech) that indicate tentativeness or emphasis.
3. Be Pessimistic.
Explicitly express doubt that the preconditions for the hearer to oblige are held. This way the speaker is supplying the listener with a way out, hence it is less of an imposition.
You’re probably busy, but I wonder if …
You wouldn’t happen to have an extra pen, would you?
4. Minimize the imposition.
I’m not asking for much, a small contribution would do
Give me just a second (this usually means more than a second).
I just need to borrow a little bit of flour (‘borrow’ being a euphemism for ‘take’).
5. Give deference.
Pay respect; acknowledge the hearer higher social status. By that act, it is communicated that the speaker is certainly not in a position to coerce the addressee into compliance in any way. It also indicates the absence of risk to the addressee. This can be done either by elevating the addressee or by humbling the speaker himself.
Excuse me sir, may I sit here?
I’m just no good at this, can you help?
Please accept this modest gift.
Admit the impingement.
Acknowledging that what you’re about to say is an impingement conveys the message that you’re not taking the face threatening act lightly.
I’m sure you must be very busy, but …
I know this is a bore, but …
I’d like to ask you a big favour:
I hope this isn’t going to bother you too much:” 
I normally wouldn’t ask you this, but …
Look, I’ve probably come to the wrong person, but …
I don’t want to bother / interrupt you, but …
I hate to intrude / impose, but …
I’m terribly embarrassed to have to admit …
I hesitate to trouble you, but …
You’ve never bothered me, I know, but …
I hope you don’t mind me saying this, but …” 
Give overwhelming reasons.
The speaker can “claim that he has compelling reasons for doing the face threatening act (for example, his own incapacity), thereby implying that normally he wouldn’t dream of infringing on the hearer’s autonomy:
I can think of nobody else who could …
I simply can’t manage to …
I’m absolutely lost …” 
Excuse me, but …
I’m sorry to bother you …
I hope you’ll / Please / Would you forgive me if …” 
7. Impersonalize the speaker and the hearer.
Dissociate both parties from the face threatening act.
“One way of indicating that the speaker doesn’t want to impinge on the hearer is to phrase the face threatening act as if the agent were other than the speaker, or at least possibly not the speaker or not the speaker alone, and the addressee were other than the hearer, or only inclusive of the hearer. This results in a variety of ways of avoiding the pronouns ‘I’ and ‘you'”. 
It would be appreciated … (by me)
It is expected … (by me)
If it is possible … (if you can)
Further details should have been sent. (to us by you) 
I got delayed; I’m sorry. (the passive ‘got’ enables the speaker to avoid mentioning who delayed him or why was he delayed).
I was wondering whether you could … (instead of ‘I am wondering’; the speaker distances himself in time from the face threatening act).
Present the face threatening act as a general social rule; claim that the speaker does not want to commit a face threatening act – he is bound to do it by the circumstances.
We don’t drink around here.
Drinking is not allowed.
Nominalization (converting a word or phrase into a noun) can remove either party from being the noun, thus distancing him from the event.
Your sleeping was disappointing to me instead of
I’m disappointed that you slept.
8. Go on record as incurring a debt, or as not indebting the hearer.
I’d be eternally grateful if you would … 
I’ll never be able to repay you if you … 
I could easily do it for you. 
It wouldn’t be any trouble; I have to go right by there anyway. 
When the listener is in our social circle, and we need to be polite, we should Show Friendliness.
 Politeness: Some Universals in Language Usage. Penelope Brown and Stephen Levinson. Cambridge University Press, 1987.
Power & Solidarity by Mary Shapiro