When a person enters into a calming state, such as meditation, yoga, hypnosis, relaxation, quietude, prayer, etc., on a regular basis, gradually the state of calm that previously was only experienced during the practice and maybe for a little while afterward, turns into a trait – a characteristic, an attribute, a quality – of that person. This is why regular practice over the long term is so crucial. If you want calm and focus to be a part of you all of the time, you need to practice it. That’s why it’s called a practice.
You could say that you've done intensive practice in stressing and over-stimulating your nervous system and you’re really good at that now. You might even say it’s second nature, you don’t even have to think about it anymore, like driving the car or brushing your teeth. Now spend some time with the practice of calming, letting go and emptying out the mental/physical/emotional trash.