Words are in adequate to describe the emotion aroused by the prolonged movement in unison that drilling involved. A sense of pervasive well-being is what I recall; a strange sense of personal enlargement; a sort of swelling out, becoming bigger than life, thanks to participation in collective ritual.
Millions of soldiers have risked and surrendered their lives in was because of the primordial connection they felt toward their fellows. Families are often held together through thick and thin by that feeling.