John Green wrote tons of great pieces in his early days as a mental_floss contributor, and the “Not So Different After All” chapter in our book What’s the Difference? might have been our favorite. Here's just one example of John explaining how two seemingly unrelated things were quite similar on closer inspection.

Abraham Lincoln and Two-Year-Olds

Lincoln: Had a “willful, impudent, childish” wife (to quote her biographer)
Two-Year-Olds: Are generally willful, impudent, and childish

Lincoln: Openly wept the first time he heard “The Battle Hymn of the Republic”
Two-Year-Olds: Openly weep for any old reason

Lincoln: Once said of do-nothing General George McClellan: “If McClellan is not using the army, I should like to borrow it for a while.”
Two-Year-Olds: Also constantly want to take stuff away from you

Lincoln: Most famous speech, The Gettysburg Address, contained exactly 272 words
Two-Year-Olds: According to a Harvard University study, the average two-year-old has a vocabulary of exactly 272 words (“civil” and “war” not among them)