Personally it’s crossing the freeway where I live. My city has about 100,000 people but only six roads cross the freeway, with three more wayyy on the outskirts that are basically detours. There are also only a few pedestrian bridges that cross it, and zero pedestrian tunnels. The way our freeway works is it goes around downtown with the ocean to the south and west, so people live on the outside of the freeway and then commute inwards. This means insane bottlenecks with miles of cars in both directions trying to get to the other side. It doesn’t help that our four freeway entrances are also at some of these tunnels / bridges, which means people who need to get on or off the freeway are also present. In general it’s a shitshow and I’d really like to see a few more bypasses to prevent this congestion in the future.
I’m in the UK, so our planning snafus aren’t anywhere near as egregious as those in other places, but one that endlessly bugs me in my town is how there are two parallel high streets that are one way - in the same direction.
From a motoring perspective it makes sense, but if I cycle to work, the only (legal) way to get back home is along the busy main road that runs along side the town centre, or to go waaaay out of my way to circumvent the one way roads through a housing estate. So mostly I ride back against the flow of traffic, because the high streets aren’t busy and I’d prefer to do that than tackle the main road. Makes me feel like a prick every time though.
My town has a lot of one-way roads but mostly due to really terrible futureproofing from the 1880s. Back then a lot of streets that they considered “side-streets” were incredibly narrow. Nowadays those are suburban streets that just aren’t wide enough for two cars, so they made them into one-ways.