Near the end of a phone call someone says “I’ll let you go,” and it is almost never the one being held. The person who says it is the one who wants to leave; they have found a way to hang up that sounds like setting the other person free. The other person, freed, says “thanks for calling,” and thanks them for the call they are ending. Both of them know, and neither says so. It is a door you walk out through while holding it open, so it looks as if you are holding it for somebody else.