Narcissism is actually a clever guise adopted to mask its exact opposite, which is a deep well of self-loathing, a well of low self-esteem, rather than high self-esteem. This helps explain why narcissists are so sensitive to criticism, why narcissists tend to break into outrage if they're criticized, because their self-esteem is actually much more brittle than it seems, and once they're challenged, that mask falls apart.

The best you can sometimes do is learn to take a breath, count to ten and simply accept that try as you might, no, your husband will never, ever learn not to drop a wet towel on the bed. That acceptance too counts as resolving a fight.

Older siblings get more total-immersion mentoring with their parents before younger siblings come along. As a result, they get an IQ and linguistic advantage because they are the exclusive focus of their parents' attention.

Athletes often start life at the opposite end of the wealth and prestige spectrum, but as soon as they exhibit an unusual talent for swinging a bat or sinking a free-throw they may find that the rules have been suspended for them. They are waved through school and into the pros, and incidents of bad behavior are overlooked or covered up.

All behavioral or mood disorders - including depression, OCD, ADHD and addiction - have some neurochemical components, but sufferers can still work to overcome them.

When we're awake, cortisol can fragment memories - one reason eyewitness crime scene accounts are so unreliable. But at night that very fragmentation allows creative recombinations of ideas.

Certainly, people can get along without siblings. Single children do, and there are people who have irreparably estranged relationships with their siblings who live full and satisfying lives, but to have siblings and not make the most of that resource is squandering one of the greatest interpersonal resources you'll ever have.