A world war like WW2 would set the earth straight again, people would have to work together, and respect what you have. You don't need much to be happy, people are too material and think only of themselves.
WW2 saw people working together, getting on together and doing so with very little.
The only problem is that nowadays, World war would mean nukes and the destruction of the planet. Which would put a stop to it all. But its a shame as well, as humans have so much potential, but are stuck by "society" and "conformatisum"