Not using their turn signals if the only other traffic is pedestrians.
So many times I’ve been crossing an intersection to the opposite corner where I could cross either street first, so I pick the street that won't block the car crossing the other way. They’re not signalling so I figure they’re going straight, and cross the other way so they won’t have to wait for me—but seemingly every time it turns out the car was really turning after all. So they’re stuck because they couldn’t conceive of pedestrians as traffic they need to communicate with.