Often, when I'm writing on the computer, my wife's tomcat would come up
and start circling and rubbing my legs.  If I petted him, he'd just
continue; if I ignored him, he'd sometimes start urinating.  What I
wanted, OTOH,  was to get him to stop and go away, but without hurting
or scaring him.

One day, I had a bright idea:  As soon as he started, I got up, went to
the kitchen, and put food in his dish.  That worked like a charm; he
followed me out, and stayed there while I returned to my writing.  So
I've been doing it since.

I was quite proud of my solution, for a week.  Then I realized that the
cat had trained me.