It's hard to think through the implications of living in a world where it is accepted that countries with more power simply invade each other and take land and possessions from those with less power. I can't think how it doesn't ultimately lead to broadscale instability and ultimately, war. In turn it depresses me that this is toxic to the humanity progressing and solving its bigger picture problems.
You can even go further, _all_ human history had stronger groups taking things from weaker groups. On the classical era of Aristotle and on the paleolithic pre-history. We sometimes forget that humanity can be cruel and work only for self-interest, we like to think that war and pillaging is something from the past, but it will be forever with us
Speaking of the 1800s, I wonder if we could learn anything about peace in a multipolar world by studying the Concert of Europe. Might be a good topic for a historian to write a book about. I'm looking right now, and it's kinda sad to see so many books about WW1 and so few about the peaceful period which came before.