I would remove selfishness and greed.
If you remove people´s will to have and possess, you remove the very reason for the existence of crime and wars.
That´s what so great about comunism. In it´s pure form, comunism is the solution for all that is wrong with the world. Everybody owns the same, everybody eats the same, dresses the same, drives the same. You don´t need to steel because you already have it. You don´t need to wage war because there are no borders, all the resources are shared. Everybody matters, no one is left out and no one is kept out. There are no classes, no elite, no poor people to discriminate and no rich people to envy. We are one and the same.
It was selfishness, egotism, greed and envy that shaped this world to what it is now, a paradise for crooks, warmongers and thiefs. Capitalism is the system of choice for the selfish and the greedy, just as comunism is for the just and the righteous.

PS:Please do not compare comunism with that aberration that takes place on some countries. China, the ex-USSR, North Korea, Cuba, Venezuela, these are NOT comunist countries. They are just compromises. For comunism to exist, we have to banish all borders and become one nation, one world. Otherwise, there will always be someone else, somewhere, to envy and to crave. And that would bring the system crumbling down.
Real comunism has yet to be implemented. No country on Earth ever tried or wished to implement REAL comunism. Except maybe Atlantis...

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"Quincitilius Varus, give me back my legions!"
Emperor Augustus of Rome.