Bart Castelijns:
...but I never deliberately set out to practice the above, it just happened. Does the feeling of 'just sitting' happen when you go through the concentration jhana's?
Depending on what you mean by the phrase "just sitting," and using what seems to be a conventional meaning connoted from its usage here, yes.
It can be a very ordinary experience. And this impression becomes even more so as one becomes more experienced in entering what is known as "jhana" or "fixed concentration" states. The mind becomes, for lack of a less flowery description and to use a favorite Tibetan Buddhist description, "luminous in its clarity" — bright, unblemished, workable,
established, having gained imperturbability. Kind of like looking into an unsettled pond that is gradually becoming settled, seeing all the debris that was once clouding the waters begin to settle and the view of the bottom becoming clean, clear, and uncompromised. One could say that things become quite mundane, yet at the same time very clear and obvious.