More than a PTTGOYN, but in the absence of a Ridiculous Things That Have You Seething thread - unnecessary 'traffic calming' measures.
The worst examples being where they've built the pavement out into one lane, usually on the way in or out of a town/village, presumably just to annoy everyone by making them queue at busy times.
Who thought forced queuing was a calming measure?
Also the small speed bumps, which vans and trucks can straddle without slowing down while smaller cars need to slow to a crawl while still destroying their suspension in the process. Not to mention the road surface on the far side of the humps being ripped up by the impact of all the traffic bouncing over them.
Raging.