Very sad book. It's a serious, thoughtful piece of work, for sure, and I apologize for my proclivity towards bathos which compels me to summarize the book thus:
Stevens (in Dalek voice): Duty and dignity are the most important. What is this thing called banter? Explain! Explain!
(His father dies, and a girl who likes him marries another person.)
Stevens: I did my duty. I did my duty.
(Years later, he goes on a roadtrip and has a reunion with the girl.)
Miss Kenton/Mrs. Benn: We could have been so good together.
Stevens: This has been a nice chat. Goodbye.
Stranger on the pier: Obladi, oblada, life goes on.
Stevens: I remember Lord Darlington. I think I'm having some kind of epiphany. (Weeps.) This is... emotion? (Then back to robot-mode) Now I should really practise my banter, then maybe I shall finally unlock the mystery of humanity.