When people become angry IQ points are rapidly lost. At the same time, there are many who have never learned impulse control. I find it amazing there are people will to commit murder over some minor issue risking a life in prison.
I think most people here know about the marshmellow test where children are presented with a treat right before them and then told if they resist eating the treat for some period of time, say 10 minutes, they will receive 5 additional treats. This test has been carried out many times I've read. It happens that the children who best show impulse control are from higher socio/economic households. Furthermore, these children go on to have better outcomes later in life. So clearly, impulse control is learned early in life.