This statement was inspired by my experience a long time ago. I disagreed with my manager about a matter, and he asked me to think outside the box.
Later on, I realised whenever he said to think outside the box, what he meant was from his point of view. How ironic!
Thinking outside the box means exploring all possible points of view and ideas, including those different from the person's own. This level of abstraction is challenging at first because people value their opinion and statement more than others.
Whenever you hear someone says, "Think outside the box", reply with, "Whose box?".
Persevere, and you get to that place.