What can get from doing zazen

Zen instructors teach us that should not expect a merit from meditation and I agree.
Some kinds of meditation group let learners focus on a question such as "What is I",seeking an answer within themselves.
I don't follow such set a goal to do because I am tired of thinking on one conception.
We humans as known as thinking animals always think too much, sometimes a thought thinks itself.
We need to think of living a life,to do a work,to make a relationship with others, to gain self satisfied desires, to achieve purpose...but some people think too much about past happenings,a relationship which is broke up,sickness which came from wrong diets...
Those things whether good to think or not,they can't make it better by thinking.
By think deep the reality never change.
Every present situation only can change by doing,actually do to change the energy.
So simply sitting is the actual doing.
When a body keeps doing still,the mind will bring thing to do such as past things,some memories,concerning, worries, a desire that want to have...there are a lot of thought even are not linked to each other.
A thought to just to think.

See the way of thought,how they work,come and go,booming and disappearing.
A zen teacher once said,just see as if watching a passing train in front of you.
Thinking is just like he described, it is a passing train so we can't catch up.
By see a thought the mind begin to calm down.

So you can get calmness by sitting.
However it is indescribable if someone actually don't do,it cannot be described by reading,by knowing.