I shall return to the subject from time to time. My messages will now revert to the more usual style.
Real life has people in it.
This is a bit unfortunate because it messes up the neat thinking that can be done with problems that contain no people. Problems in school textbooks are relatively easy because all the information is available and any people involved do as they are told. Not so in real life where people can be unpredictable, complex, difficult and downright perverse. So there is a big need for an 'attention directing tool' which looks exactly at people. At least if you look in the direction involved and try to guess at their thinking you will be much better off than if you try to ignore them.