Just 21 years later we were at war again, arguably because the settlement at the end of WW1 was so bad.
As far as I can see we only got involved in WW1 (sorry, ordinary folk were made to get involved) because our elders and "betters" had agreed nonsense alliances and stirred up hatred.
The kaiser may have been bad, but I doubt the masses of Germen men and women were. This is the same nation that just 50 years earlier had seen the first playing of Ein Deutches Requiem by Brahms; a nation rich in culture. Hitler's evil was arguably a result of the settlement following WW1. Looking back at all the arguments for and against WW1, nothing has changed my views: it was a bad war that should never have started.
Unless we are careful we in the west will believe our own propaganda and get involved in a new European war over parts of Ukraine. There are always several views of a particular situation.
We must learn the lessons of history. Don't let tyrants have it their way but don't fight pointless wars. Listen to the real people, not politicians, military generals and aristocrats. Ordinary people matter most - listen to their voices.