“Say, for example, you are feeling a particular sensation which may be due to the food you have taken, which may be due to the atmosphere around you, which may be due to your present mental actions, or which may be due to your old mental reactions that are giving their fruit.
Whatever it may be, a sensation is there, and you are trained to observe it with equanimity and not to react to it: but you keep on reacting because of the old habit pattern. You sit for one hour, and initially you may get only a few moments when you do not react, but those few moments are wonderful moments.
You have started changing the habit pattern of your mind by observing sensation and understanding its nature of impermanence. This stops the blind habit pattern of reacting to the sensation and multiplying the vicious cycle of misery.
Initially in an hour you get a few seconds or a few minutes of not reacting. But eventually, with practice, you reach a stage where throughout the hour you do not react at all. At the deepest level you do not react at all. A deep change is coming in the old habit pattern.
The vicious cycle is broken“
S.N.Goenka
Vipassana
Astitva Meditation 