I spotted the start of a parking thread today, although I think it's going to be a matter of who can wear down the other first, not a live one (sorry!).
Yellow Neighbour has two cars and one parking spot next to their house. They have used the adjacent visitor space as long as they have lived there. In fact, the previous owners did as well. It became customary for everyone in our bit of the road.
Green Neighbour moved in recently. They also have two cars and only one parking spot. They started by blocking themselves in at the end of their driveway, but have now moved that car to the visitor space.
Yellow Neighbour's only option is to block themselves in as well, so every day one of them is going to be pissed off! Me and another neighbour are in between them both, and we have longer driveways so aren't involved.
POTENTIAL PLOT TWIST: there is a second visitor space across the road, which a different neighbour also customarily uses for their second car, but I don't think Green has realised that is a visitor space yet. It is also closer than the current one....
(I have added the mandatory diagram but it may need to be approved)