Politeness is a bit of an old-fashioned mentality I suppose these days (although not at Pilgrims'), but if you drill down into it there is a lot of psychology going on.  

1) What is the purpose of manners?

2) What does it say about us?  

3) What does it say about the people we interact with?

4) What is the effect of good manners?

The purpose of manners could be manifold: to put someone at ease, to show appreciation, to demonstrate respect, to adhere to social norms.

It reveals things about us: gratitude, respect, humility, grace.

It shows what we think of others:  we are equals, I respect what you do, I appreciate what you do, I needed help and you did so.

It affects others:  makes them feel needed, appreciated, respected, considered, important, valued, and it makes a good impression.

I suppose the opposite is true too, when manners are poor or lacking.

What I feel is more deeply significant is the fundamental base which underpins manners.  To me, good manners reflect that someone puts others first, considers them of equal value, recognises that everyone's efforts are worthy, and knows that all people contribute to their lives and basically make themselves better company to be around.  A young man who looks you in the eye, thanks you for your lesson, holds the door open for you when you're struggling with books, asks how you're doing, is a joy!  A real joy.  And the one that skulks away at lesson's end, shows you no interest, and takes all your efforts for granted, is the one that leaves no mark on your world.

I have seen many a polite boy turn into a polite young man at Pilgrims'.  Many of your sons will be amongst those who leave here with good manners, and go on to leave their mark on the world.  

Mr Shroff