Animal Instinct

The feeling of ( ) was so pervasive that it even overrode the instinct for ( )
And as you bowed your forehead never touched the floor
And you are waiting for that one moment when the ( ) you never heard
and all the things you ( ) come back
to haunt you
And now you remain a sealed envelope.
And of course nobody knows of all these words the letters inside contain.
And you will say nothing because wasting words is a waste of time.
And no one understands the disease that slowly spreads upwards, rot to the brain.