~ How to make hard choices?
Different time periods form different characters, as do different nations, because people born in those times and places have different experiences. The more synchronized events are, as Newberry has noted, the stronger this is. In a mass media society with relatively fast technological and social change it makes sense to speak of generations. The character of people born 20 or 30 years apart in modern societies will be different, and within cohorts similar experiences will tend to create somewhat similar patterns of character.
Society is nothing except people and their creations and interactions over time. Walk down an old neighbourhood one day, and look at the buildings, the road, the trees and think about all the people who made everything you see, and all the people behind those people. Read the laws, and know that people made those, and enforce those Different Characters