Surprisingly manners is one thing, I never forget. I guess I go on the idea that if I want ones to be courteous to me, then I should be back.
However, thinking about it, I admit that I do struggle with asking ones how they are, but that is because mostly people are very quick to pile into their ill health and well, I have a whole pile myself, but keep quiet because I am well aware that people do not always want to know and so, it gets to the point, I feel almost begrudging asking, especially if the person is known to never care about how anyone else thinks.
I tend to be over exuberant ( if that is possible) with manners, the extent that I do not want to cause others to have to be polite to me and a prime example is the one you gave ie about passing things across the table. I hate the idea of disturbing or inconveniencing others when they are eating and thus, try in vain to get the things myself, but inevitable, I bring myself to notice because my arms are not long enough!