Those radar speed limit signs that blink at what seems like 50 times a second if you go 36 in a 35 zone are very annoying. To be fair the blink threshold must be configurable, but whoever installed them around here didn't have any common sense and set them all to the speed limit exactly.
There's one near me that's set to 45 in a 55. Every time I drive past it it gets a little closer to going missing. It's a minimum effort install on a wood post and it's right near the road to enter a new bougie subdivision in an otherwise rural area so it's almost certainly a cheap attempt to make a complainer go away.
I also hate the ones that are exactly at the spot where the speed limit changes and still flash you aggressively in the distance. Yeah, I'm going faster than 35 because the speed limit is 55 where I am and I'm still slowing down.