WWI was very wasteful in terms of young lives lost, with over 16,000,000 troops and civilians dying and another 20,000,000 wounded, many with life changing injuries that they had to carry for the rest of their lives. On top of that there were also the mental scars.
And of course despots that will make the populations pay any price for them to cling to power still lead countries. Russia, China, Syria and North Korea to name the more prominent ones. Putin is heading towards being the cause of 500,000 deaths with 250,000 in Chechnya, 200,000 in Syria where he backs and supplies Assad with arms, 6-12,000 in Ukraine, then there is Georgia, Transnistria etc. Many people who oppose Putin and his proxies like Kadyrov in Russia are simply disappearing, we only get to hear about the more prominent murders. But this is small fry compared to the deaths there will be, if he has the opportunity to start throwing round instant sunshine in a desperate attempt to cling to power.
It is already shaping up on who will be allied with who in the coming WWIII. IMO weak Western leaders who are taking the path of least resistance where it is politically easier than standing up and preserving the current collapsing world order and the constant breaking of International law by certain countries are as culpable (like they were in the 1930's) as the evil people destroying it.
Psychopaths and power are a very dangerous combination, along with weak appeasing democratic politicians, who aren't interested in anything beyond courting voters and paying any price to cling to privilege and power, where this is now an end in its own right. IMO between them they are going to be the cause of the world's next mass extinction through WWIII and the use of nuclear weapons. Humans will probably survive, but it will be mainly in the Southern hemisphere. It's a gloomy prognosis but sadly IMO a realistic one.
Russia, China, North Korea and Iran are all expanding their military and nuclear capabilities, while in the West with a few exceptions like Poland, Lithuania and Estonia we are all still cutting outs. Whoever wins the UK election will cut defence spending so it is below the NATO 2% of GDP, which is why only UKIP (who have no chance of gaining any power) is saying the will keep to a minimum of 2% of GDP. Many parties are offering to gift Putin the UK's nuclear deterrent.
You check out the political parties
lists of lies manifestoes here, including 'Foreign and Defence':
http://www.bbc.co.uk/news/election/2015/manifesto-guide