At its core, Zen is a personal experience that takes place right here and now. This is a great mystery. So we try to direct our attention to the present and watch it pass. It simply happens.
What unfolds for you is never the same as what I am experiencing at this very moment. When we try to put this personal, immediate experience into words, we fall behind it: we form sentences that describe what has already passed. That certainly has value, but it is not Zen itself.
Zen practitioners therefore sometimes try to inspire their fellow practitioners with gestures rather than words. There are many stories about this: someone simply raises a finger or kicks the other person in the butt. It is an attempt to nudge a friend into this immediate present moment and thus provoke an awakening.
However, in Zen, I do not view practicing and experimenting, together with the accompanying thinking, supposed doubts, and failures, as a path to a goal, but rather as an expression of Zen itself and of our Buddha-nature. Enlightenment is like being struck by lightning. Personally, we cannot do much about it. It happens as soon as we remember ourselves as practitioners of Zen. Again and again. Our task, then, is to forget it.
Once lightning has struck, we should no longer do anything that has to do with Zen. Practicing Zen is basically a pathetic attempt to beg for lightning to strike again. We are trying to provoke or bring about enlightenment. That is completely crazy. And yet nothing better seems to occur to us than exactly that. That is why all Zen practitioners are truly fools.
Zen cannot be practiced. True Zen is non-practice. It is an expression for something that passes us by. We know this, and yet we practice anyway.