Charles Dickens (maybe unwittingly) borrowed the phrase in “Oliver Twist” when he described a hungry boy daring to approach the orphanage supervisor with a “Please Sir!” in order to ask for a little more food.
It sounds rather trivial but it suggests one of the highly serious fundamental rules of Jewish prayer.
We could burst in and shout “Food!” to God but instead we make an approach, we address him with a “Please Sir!” and only then do we spell out our request.
The b’rachot have this structure: first, “Blessed are You, Lord our God, King of the World”… and only then do we utter the crucial words. The Amidah begins with three paragraphs of praise of the Almighty and only then do we articulate our requests.
There could be a criticism of this practice – doesn’t it seem as though we are flattering the Creator, buttering Him up as it were, to get Him on side?
The criticism is only valid if we forget that God has no obligation to do anything for us, especially if we don’t deserve it.
What we are doing by saying “Please Sir!” is to acknowledge that everything comes from Him and if He answers us as we wish it is a mark of His concern and graciousness, not something He owes us.