Since I began my professional "career" I've gravitated steadily from larger to smaller organizations. At first this was an intuitive rather than a considered objective (I'm an INTP, remember?), but over time it's become an explicit requirement. At one point I tried to codify the "acceptable" size for an organization in terms of numbers of employees, but I've come to believe that it's less about absolute numbers and more about the mindset that prevails among the majority of employees. For me, the best possible circumstance is a company that's somewhere on the spectrum from unformed idea to Pirate Ship. As soon as it passes from Pirate Ship to Going Concern, it stops being fun for me and I need to start over.
Since Pirate Ship is a technical term only to me, let me explain. An organization is healthy as long as its survival is sufficiently in doubt that each employee feels a primary responsibility to ensuring the survival of the firm, and a secondary (or lesser) concern for their own position within the hierarchy. The vitality of this "us against the world" mentality depends (to a greater or lesser extent) on the prospect of treasure somewhere on the horizon (i.e., it cannot be sustained in organizations where the prospect of treasure has dimmed to the point that jumping ship and taking a risk on a new captain and crew seem like a better bet). But it can if, despite remarkably long odds, a plurality of the crew believe that a rich prize might still be lurking beyond the next atoll. The scale at which this condition ceases to exist is conditioned equally by the nature of the opportunity being pursued and the quality of the leadership at the helm.
As soon as an organization reaches the point that its survival is no longer in doubt (or that the average participant no longer feels that his or her individual contribution is material to its survival), corruption begins to seep in. Rather than focusing their energy on the external fight, team members begin to put their efforts toward extracting the largest share of the available pie for themselves, and growing the pie (or making sure there's pie available in the future) gets correspondingly less attention. These are often the same people who fought so passionately for the survival of the enterprise in the early days, and their response to the organization's condition is a natural one, not at all inconsistent with their earlier priorities. Treasure and adventure were always their aim, and as the quality of the adventure wanes (due to diminished uncertainty about the outcome), the emphasis on treasure can only increase.
I suspect that pretty much everyone has an appetite for both treasure and adventure, but for a lot of reasons most people spend their lives in organizations where the fight is on the inside rather than against the world. I feel lucky to have discovered a different way of working, and for me the pirate's life is the only one worth living.