James Gould Cozzens on impulsiveness and the fateful role it can play: 

"Could he say that confronted by a certain situation he had taken on principle certain steps? He had in fact acted on impulse, in a mood or state of mind in which instead of doing what he really meant to do, he did what he meant to avoid, refused what he really wanted, and with unprovoked pique, out of hand, in a minute, came to new and definite decisions that might--more than might, must!--affect his whole life."