it's a question and answer site. people ask questions and get answers - no need for TIA or a thanks afterwards IMO.
I think some responders like being the first to answer/ the best answer anyway, so they get their own rewards :)
I think good manners have practically ceased to exist emmie. It's harder for me (being 70) as I can well remember when manners counted for something.Yes,they might have been a bit restricting,but at least you knew where you were.