Some non-noticers/appreciators are the ones with the problem; they mislay their nose, nevermind other people!

My husband was an executive at a business and a secretary quit and one of her complaints was that he never said hello to her, never smiled or greeted her. She did not work for/with him at all, he just walked past where she was sitting occasionally but he never "saw" her at all. When he was told she had quit and had mentioned him, he had no idea who she was even!

I think if we want to be noticed by certain people, we sometimes have to jump up and down in front of them and see what happens. They could just be people who don't "see" very much. I can arrange an entire surprise party for my husband, with him in the same room and he'll be surprised.