Heh. I was in Atlanta a couple weeks ago and I saw what appeared to be an odd roadsign. “Keep Moving.” Once I stopped wondering, “what the fuck?,” I realized that as you exit the expressway you get dumped into your own lane. There’s no reason to stop as you go around the corner to your right.
We’ve got lots of those around town, particularly in Gwinnett County (where, IIRC, you were meeting up with other Dopers). A lot of them are in the type of location you describe, while there are others that are at non-expressway locations where traffic flow makes it desirable for drivers to be able to make a right turn without waiting for a gap in traffic coming from the left on the cross street. Unfortunately, a large number of local residents seem to be unable to read these signs, and stop dead still in front of them, causing nearly infinite frustration to the rest of us.
Either that, or they’re all out-of-towners who have the same reaction you did.
an old favorite - back in my dorm days, there were “kitchenettes” - 3 stoves in a room, to serve the half of floor that I lived on (about 40 rooms). One day, a sign appeared. “Please do not steal the oven knobs”. We went to our rooms and started thinking 'gee, what could you even use them for???" and sure enough, within days, the oven knobs started disappearing. To this day, I think it was a psych experiment.