Yeah. My destructive thougts and self-doubt become replaced by a feeling of calm self-assurance and living in the physical present. Enjoying a book, cooking, etc is suddenly way more enjoyable without the white noise of preoccupation.
Sunnuvabitch! I just wrote an awesome reply and my internet reset and swallowed it up.
I totally know what you mean and also have come to the conclusion that overthinking is the culprit.
The tricky thing about overthinking is that if you TRY to make it go away, you're actually just thinking more. That makes sense because thinking is driven by needs and wants (agenda). I see it like this. Your mind is going to create thoughts based on associations with mental or environmental stimuli. There's a basic level of thinking that you can't avoid. But when you have an agenda, you complicate your thinking more and create more thinking. The agenda can be very subtle like get food, look smart, look confident, think of yourself as superior, stay focused, get happy, think less, be successful, whatever. When the agenda is active, your thinking takes over and you get absorbed in your head. The more serious the agenda goals, the deeper the level of absorption and the more severe the disconnection between you and your true self become. The true self is the source of the stability you want.
The problem with most meditation techniques--the problem with any technique--is that it puts you back in agenda-mode. Just think. Okay, breathe. Okay, do this, do that, blah blah blah. In my own experience, it's a disaster and a recipe for frustration. The solution is to STOP the agenda. Completely. Stop trying to do anything with your experience and stop trying to solve anything. Just be quiet and see what's here. Anxiety? No problem. Meet it. Mania? No problem. Depression? Despair? Desperation? When I'm patient and listen to what's happening rather than try and outsmart it, things begin to change. The agenda melts away. I still have thoughts, but they're don't have the same gravity as before. Most importantly, I have intimacy with myself and my body. At first I usually feel some tensions and vulnerabilities (for lack of better term) in my body, but they fade away and things calm down dramatically. It's the method of no method.
If you want to investigate it more on your own, you can read about Zazen (just sitting) or Shikantaza (a specific form of Zazen that turned into an entire school of Zen called Soto Zen).