There's an amusing piece on the BBC News website about the auctioning earlier this week of a letter written by an elderly Charles Darwin, in which he complains, "I am tired to death with writing letters; half the fools throughout Europe write to ask me the stupidest questions."
It's little insights like these which make the Darwin Correspondence Project by far the best way we have of getting inside the great man's head. If I had my way, they would be awarded the Nobel Prize for Literature.