I've been thinking about this (only in the back of my mind, it's not preying or anything

) and half of the problem, I believe, relates to the person rather than the scenario.
Not only did she not say thank you, she did not look up, she did not acknowledge me. I felt like a doorman at the Ritz, only without the tip. If, however, it had been a nubile 20 year old blonde, I probably would have thought 'bitch...althought that was pretty hot'. Maybe I have some deep-seated preconception that all old women should be lovely friendly grandmother-type figures.
Some of you are probably right in saying 'if you only held the door because you expected thanks rather than just to be nice, then why bother holding the door' or similar. However is that really how humans work, that they only do nice things because it makes them feel nice? Maybe so.
Manners and expectations make an interesting topic. Most of it is probably ultimately self-serving, much like making charity donations

.