If mankind started out without any negative traits that like greed, ego, anger etc., how would it shape our civilization up to this date? Would we have created the perfect utopia or made ourselves extinct long ago? Are our flaws holding us down or are they the reason our society made it to this point?
The reality is that it is degrees of flaws that evolved to something sustainable. If there was some evolutionary benefit to going murderous angry if say a person looked at you wrong, then that is how we likely would be.
While certainly there are extreme cases in individuals, as you say, these are emotions needed to survive. And the overall level of greed and ego and anger would maintain some level most beneficial to human survival.