The more you focus on Cletus Kassidy, the scarier Carnage becomes. As said before Carnage comes more into play nearing the final act. Cletus is the core and meat of the film. Carnage, once unleased, is more of an uncontrollable force of nature and becomes more and more of a killing machine; killing as many people in sight rather than stalling to observe blood matter. Carnage loves the act more than anything else because it allows him to give into these primal instincts that he is very fond of. This is a guy who wants worldwide anarchy and for people to become pre-civilized. So he'd rather rampage through a city killing everybody in sight rather than stopping at one of the victims to kill them slowly, he wants worldwide chaos- stopping doesn't do that, killing MANY in his way achieves his uncontrollable goal that the symbiote strengthens and scares Venom away from him just like in the cartoon (but in a more adult way of thinking).