European nations began World War I with a glamorous vision of war, only to be psychologically shattered by the realities of the trenches. The experience changed the way people referred to the glamour of battle; they treated it no longer as a positive quality but as a dangerous illusion.
All of us grow up in particular realities - a home, family, a clan, a small town, a neighborhood. Depending upon how we're brought up, we are either deeply aware of the particular reading of reality into which we are born, or we are peripherally aware of it.
Alliances and partnerships produce stability when they reflect realities and interests.
We are actually living in a million parallel realities every single minute.
Science fiction is trying to find alternative ways of looking at realities.