switchlogic:
if I move aside to let someone past or hold a door etc and they don’t say thank you I say ‘you’re very welcome’ loudly.
Exactly what I do.
If on a back road, I often pull in to let them (usually a rigid tipper for some reason,) past.
Quite often they will pass me slowly without acknowledging I have give way, they usually have their window down, so I shout the same.
Just downright ■■■■ ignorance, no excuse for it, manners and courtesy cost nothing.