Would life be easier (socially, career) for an introvert or extrovert?

In my experience extroverts have an easier passage through life and are usually more successful.

actually, one isn't better or worse. they're both equally valid, depending on society's needs at the time. check out the book Personality by Daniel Nettle (http://amzn.to/bpiok8) and you'll discover that research on the Big 5 personality traits proves cross-nature (humans and animal kingdom alike) that when nature/society needs a certain trait, like extroversion, then extroverts will come out on top and be the survivors. however when nature/society requires more introverted or contemplative personalities, then extroverts actually stand to lose, and introverts survive. same with other personality traits.

extrovert

Extroverts tend to be at the centre of everything that is going on. Whether it is in school or work or out socially. You can spot them sitting at a table surrounded by 5 or 6 people and they are all paying attention to what that person is saying. They also tend to know what makes people 'tick' and can say the right things to them, a trait used by conmen and pool hustlers.