Again, a great question. Like any habit, the longer the habit is in place, the more conditioned we are to head down the same path. The same is true for thoughts. The more often we believe a certain thought, the more etched in our brain the thought becomes. It becomes the "nee normal" and every time that thought is "practiced" it just grows stronger. (like a muscle, the more it is used the stronger it becomes). So when you have a particular thought, like "My tinnitus is never going to go away---I have tried everything" and you think this thought time and again, the mind grows stronger around the thought making it harder to alter. That is why it is important to practice being flexible and adaptive with our thoughts. With habituation, the mind needs space to think new more adaptive thoughts around tinnitus. By opening up the possibility for change and possibility, the mind creates new pathways (such as "I can heal and change my perspective on tinnitus") that can open us up to new ways of seeing things and better promotes habituation to tinnitus.
Warmly,
Jennifer