It’s possible someone could have smarts in some areas, but absolutely no common sense.
Without common sense, how can you understand people and why they are the way they are? You would think in order for you to gain educational knowledge you would have to have common sense. It’s possible for someone to know and master school instructions because the material is there for them to study.
In life, there are no guaranteed answers so you have to study your surroundings and observe the people you come encounter with.