I'm insatiably curious about human nature.

Naked lions are just as dangerous as elegantly dressed ones

...remember the dangers of the New Groupthink. If it's creativity you're after, ask your employees to solve problems alone before sharing their ideas. If you want the wisdom of the crowd, gather it electronically, or in writing, and make sure people can't see each other's ideas until everyone has had a chance to contribute.

When you go to a football game and someone offers you a beer [...], they're really saying hi, have a glass of extroversion.

Introverts, in contrast, may have strong social skills and enjoy parties and business meetings, but after a while wish they were home in their pajamas. They prefer to devote their social energies to close friends, colleagues, and family. They listen more than they talk, think before they speak, and often feel as if they express themselves better in writing than in conversation. They tend to dislike conflict. Many have a horror of small talk, but enjoy deep discussions.

we have two ears and one mouth and we should use them proportionally

All personality traits have their good side and their bad side. But for a long time, we've seen introversion only through its negative side and extroversion mostly through its positive side.