Action to change ourselves

What is the difference between taking an ineffective action and inaction? I think most people think they are the same and in fact they’d rather take no action to save the costs of the ineffective action.

But I beg to differ. How did you know the action you’re about to undertake is an ineffective action? What are the factors driving effectiveness? In taking the action, do you not discover something new? If nothing changed on the situation, did anything change in terms of your knowledge and capabilities?

We tend to think more in terms of how we change a situation rather than change ourselves. But perhaps the change that we need in ourselves is way more pressing than the situation.