"The mantra of sharing your work and involving everyone in decisions naturally leads to inviting and copying people into things that add no value to them, or you."
Fred Brooks, in his book The Design Of Design, includes a section on "The Magic Power of Teams Of Two". In his opinion, large teams cannot get anything done, and most innovation comes from individuals, but Brooks feels that teams of two people are the sweet spot for innovation. You and one other person -- if that other person can challenge you in the right way, offer a different perspective, or fill in holes in your knowledge, then instead of slowing you down, they speed you up.
I personally have found that meetings of two people (me and one other person) are where all the most important conversations happen about solving problems or plotting strategy. I wrote about that in "Truly Agile development revolves around one-on-one meetings, not daily standups":
http://www.smashcompany.com/business/truly-agile-development...