Often it's not so much that people get used to it, as that the yellow lights are often set too short to react to in time (and safely) to avoid running the light

Often it's not so much that people get used to it, as that the yellow lights are often set too short to react to in time (and safely) to avoid running the light. If people have to stand on their brakes to avoid running a yellow-turning-red, it's too short.