Stop except if turning left. Stop except if turning right. Stop when going straight, etc., etc., etc. Sometimes they appear totally random and make no sense at all.
My neighborhood is full of stop signs on straight streets to let in side traffic from seldom used streets. We like it that way because it is residential and we don't appreciate people speeding through where there are kids, old people walking dogs and the like. So it makes sense.
But you get out in the country here where houses are a half mile apart or more, and they are still doing this kind of stuff. I swear it is nothing more that a way to raise revenue on people unfamiliar with the idiosyncrasies of local road design.
There’s a “stop except right turn” sign right near my house. My wife has had people honk at her for stopping before. She points at the stop sign.
There’s a place near Trafford where you are better off putting on your left blinker to tell people you are not turning right. “Everyone” turns right and people will pull out in front of you!