Usually there are several possible responses to a question, which means you’re traversing a tree. But essays are linear, not tree-shaped, which means you have to choose one branch to follow at each point. How do you choose? Usually you should follow whichever offers the greatest combination of generality and novelty. I don’t consciously rank branches this way; I just follow whichever seems most exciting; but generality and novelty are what make a branch exciting.

— Paul Graham, The Best Essay