Unlike what he does with Kurtz or Marlow, Conrad plainly manipulates these characters' expressions and actions to convey the message that a certain lifestyle and set of customs is comfortable to them simply because it stems from their Old World. The manager sought to recreate these customs in the new land by adjusting his physical appearence to fit the bill. The Russian preferred to keep notes in his native language rather than attempting to tackle a new one. Human society nurtures man and gives him structure. When society is taken away, so is much of man's capacity for good.
Some people express anger by killing, others by acting overeager.
For him, the laws of civilization did not apply in a largely uncilvilized continent. Throughout most of his story, Marlow implied that he was fighting with his spirit over whether or not he could ever really trust Kurtz. He was really fighting over whether he could trust man in general, to be orderly when the laws of order are stripped away. In the end, he decided that every great man, every great nation, every great people ever to exist, who would do to others as Kurtz's men had done to those in Africa's unexplored regions, invariably possesses a heart of darkness. Europe's Old World customs had taught the English, and other people under their wing, to take full advantage of all assets they stumbled upon, anywhere, even if it was at others' expense.