Are you extremely good at what you do, but don't have the world's most sparkling personality. Take comfort from this article on personality-based hiring.
Sometimes companies try to maintain a certain culture among it's employees. I think that's a great idea in many regards. I also think it's a great idea to surround yourself with the brightest people and especially people who think and/or see things in different ways than you do.
Some of the best matches made in heaven are between a sparkling, dynamic, gregarious personality and a boring, pensive, reclusive one.