One reason to avoid asking questions about someone’s behavior is that behavior is often a symptom of a lot more than a person’s core self.
Using the pyramid to the right as an example, your behavior starts with your underlying psychological types and patterns. The final resulting behavior that everyone sees gets modified by a variety of factors such as how you were raised, the schools you went to, your friends preferences, your experiences in life, the culture you were raised in and expectations at work. This means that questions about observed behavior may not help understand your underlying core self.
Another example of how behavior and core self is different comes from Linda Beren’s Core Self model. You have a Core Self, at the center, and then layered on top of that you have Developed Self, as you adapted and grew with influences from family, parents and school. Then you also have a Contextual Self, and this is what most people see from the outside, and this is where you might act differently when in front of your parents versus in front of your friends.