Part-black generally means all-black in Americans' minds. Just as part-Asian or part-Hispanic or part-anything-else usually puts individuals in those minority-groups' camps.

What people fear most about tragedy is its randomness - a taxi cab jumps the curb and hits a pedestrian, a gun misfires and kills a bystander. Better to have some rational cause and effect between incident and injury. And if cause and effect aren't possible, better that there at least be some reward for all the suffering.

There's no such thing as downtime for your brain.

The brain sits snugly inside the skull, but it's not a completely flush fit - there is still a layer of fluid between bone and soft tissue that serves as a natural shock absorber. Some shocks, however, can't be absorbed, and when the head gets clobbered too hard, the brain can twist or torque or rattle around inside its skeletal casing.

Operating-room errors hold a special terror for patients, if only because they seem like the most avoidable kind of complications. The occasional horror stories of patients who have the wrong leg removed or the wrong knee replaced generate the most headlines, as do tales of patients whose identities are mixed up entirely.

Learning to speak was the most remarkable thing you ever did.

It's a deep and all but certain truth about narcissistic personalities that to meet them is to love them, but to know them well is to find them unbearable. Confidence quickly curdles into arrogance; smarts turn to smugness, charm turns to smarm.