Non-reactivity is to observe your thoughts and feelings and any environmental circumstances with a more detached outlook. Instead of labeling events (such as sensations, thoughts and feelings) in your life with ‘good’ or ‘bad’, you learn to accept things as they are without reacting to them.
I’m having some trouble with the concept and with the practice itself.
To accept things as they are without reacting to them seems like a sure way to not make a difference. You move and change things in your life as a reaction to events. If you would accept (shrug and nod) anything that happens in your life, you would not progress, you would not evolve, you would not improve. How can you be non-reactive to everything and yet be stimulated to progress and improve yourself?