Ah yep I think U get what you mean now. You're talking about too much introspection right? Which can lead to rumination, depression, and anxiety. I agree that too much navel-gazing isn't healthy, but none at all isn't healthy either. You ideally want a balance where you're neither avoiding dealing with your deep inner problems, nor getting stuck endlessly self-analysing in a loop. At some point you need to go and actually live your life.

I'm not sure reading really has anything to do with it though; other than being a quiet activity that might promote introspection. If anything it might distract you from it. As someone with a fatigue condition, I was at my worst mentally when I was stuck in bed for hours every day, with nothing to do but stare at the ceiling and think. Just completely alone with my thoughts. Not enough energy to distract myself at all.

Personally, I feel like 5% of people are overly introspective to the point of causing symptoms, 0.1% has a healthy balance, and the other 94.9% is the other extreme, and have never once even stopped to reflect in their entire lives; terrified of their own thoughts and feelings. Which is unhealthy in it's own way. Repressed issues tend to bubble up in unexpected paths (e.g. bad habits, addictions, behavioural issues)