I'm extremely interest the general feeling and views societies had in the past: how they perceived the present and the future, as a whole.
Objectively life has become better and more comfortable for the vast majority of humans since then (Hans Rosling does a beautiful job of exploring this).
But I do think that perceptions and feelings matter, and even though material wellbeing is a prerequisite to that, so is also the general feeling and view that those around you hold, and in many ways I feel we've gone backwards in that.