>>33487408 (OP)Imagine a large expanse of earth/dirt, like a field. Imagine a wagon crossing it. Initially, it's hard work, because it's rough earth everywhere with no path. But suppose the wagon keeps crisscrossing in the same place. After a while, it forms tracks, and the going gets easier; then the tracks get deeper and form ruts. It gets easier and easier for the wagon to go that way; but eventually the ruts get so deep that the wheels of the wagon are trapped in them, and it can't turn any more, so it has no choice but to keep following exactly the same path over and over - even if that might not actually be the route you want to take.
Your mind works like this. It forms patterns of thought. And if those patterns are repeated they become easier, until eventually they become binding: you can't think any other way, and your mind always follows the same path and slips into it automatically.
What CBT does is to create a whole new path across the field - create new tracks and ruts - so that the wagon can follow that new path instead. (And obviously you choose where you want the path to be so that your mind goes to the places you want). CBT is a set of exercises that train your mind to create new patterns of thought, or new mental habits, that are healthier than the old ones. And if you keep doing it for long enough, the new path becomes easier and more automatic than the old one. (And the old path, to extend the metaphor, eventually washes away in the rain with no wagon to sustain the ruts).