I might have a theory about the “bad" comfort zone. I think we are talking about this zone where we find ourselves unconsciously because we have just been conditioned our whole life to be in.
We were trained so well during our educational cursus to be sheeps, to “just" give back what we were given and, eventually, graduate in the area we were able to have our best marks (thinking unconsciously this is what we are good at and meant to do).
Definitely, by repeating the same thing over and over again, we might become good, but “just" good. A sheep looking at the ground from a few centimeters will never have the same view as an eagle.
And I believe this same sheep is very able to become this same eagle when becoming self-aware of how much the program dictating his behavior was distorted by the external conditioning.
If after a self-discovery journey, it turs out this is exactly where we are meant to be, then we are already in our “best” comfort zone and we will ultimately shine.
But, if we find out how miserable we are, that we just never took a chance to reflect about what really matters to us and what we stand for, then, you guessed right, we are in this “bad" comfort zone and we will, definitely, need a great amount of bravery to change it !