Perhaps the hardest thing to get across about Zazen ... and the aspect that chases most people away ... is that human beings really cannot tolerate what it means to just be, just open, allow, let go, not chase or do ... [They can confuse] "Just Sitting" with "just sitting around", and the "Mudra" in which we hold our hands with "just twiddling our thumbs". They confuse "Nothing Special" with "doing nothing special", and sitting in the Timeless free of the clock with "killing and wasting time".
You might think it is the easiest of all things ... just to tell people to stop and "give up the hunt" for a time ... that sitting is the one space in life where there is nothing to win, nothing to pursue, nothing to think about or plan in that short space when the bell rings (our way of finding a Treasure Always Present Yet Rarely Perceived).
But rather, people quit and walk away from Zazen ... much preferring to do something constructive, less boring, pursue some dream or goal, solve some problem, deal with things, figure something out, get to the promised land which is likely over the next hill ... or the next ... or the next. People do not like to just sit and let life go and flow for a few timeless minutes, enjoying the Promised Land where they sit.