thanking-for-thanking, long buildups to requests, apologising for things which are clearly not the other persons' fault

(Assuming you mean "not the apologizer's fault" in the last one.) I don't do these things, and I don't think they're necessary forms of courtesy, at least in a peer situation--customer service calls for jumping through hoops sometimes but I don't think that's what we're discussing.

How much have you considered the level of politeness you prefer to receive as opposed to the potentially interesting/fun problem of working out what to transmit?

I suspect that I'm similar to most people in that I notice mostly when someone uses a politeness level which is not what I wanted. ;) I'm not sure what terms I could use to clarify what that level is, though.