Again and again, throughout my career, I’ve heard people talk about the difference between working in the private sector and working in the public sector.

Forget that. Any sufficiently large organization is indistinguishable from any other of the same size. Working in the heart of a 100,000 person bank and working in a 100,000 civil servant government are so much closer to being the same than being different it’s not funny.

There are those who think the difference between a start up and a large organization is simply that the start up only has a few people. It’s certainly true that organizations, as they grow, go through transitions. (This has to do with the phenomenon known as “Dunbar’s number”, after research done by Dunbar into the maximum number of people that can know one another at least well enough to trust without further infrastructure such as hierarchies, titles, reporting requirements, etc. substituting for the lack of trust.)

Not quite true, though, since W. L. Gore & Associates demonstrated that a company can grow to thousands of staff and yet maintain trust, simply by keeping its individual components small enough to remain trust communities. So something else is going on, and that something else matters significantly in considering your career.

What is missing in a start up is rigid structure. Yes, there’s structure: product developers are not the sales person, and so on. But in most organizations structure is rigid: opinions are seldom sought across structural boundaries (developers talk to developers, sales people to sales people, but not developers to sales people about a development problem or sales people to developers about a territory problem), and responsibilities are chained within the structural norms.

This is why a small not-for-profit can be quite rigid in its organization, although it shares the size of the start up. It’s also how much bigger organizations can retain fluidity even though their size has long since passed trust community size.

But, if you’ve spent your work life in one type of organization, and then jump to the other, you can find yourself in deep culture shock, and be headed for a fall.

The most common jump, for those of us who are up the career ladder, is from rigid structure to small scale, be that because we started our own venture or signed onto a start up/non-rigid workplace.

All of a sudden there are no bounds, no order. This is disorienting in many ways.

First of all, the old “organization man” is ripped up in an instant. Your role no longer has bounds. Its responsibility has deepened — the success of the whole becomes everyone’s job. Authority, curiously, is often shared: decisions are made after consultation and collaboration (but, unlike rigid organizations, quickly). Many items are “no one’s” responsibility (officially) — they’re simply handled as they come up.

If you’re used to a world of “I do this, and you do that, and I refer this to so-and-so when it comes up”, this can be culture shock. If you’re used to the power of a job title in a hierarchy determining whether or not this is your decision to make, quick and effective collaboration is a method that makes no “sense” in your experience. Likewise, looking around to see what isn’t being done (but needs attention) isn’t a part of your experience, either (since this place, like the previous places, always has more to do than there is time for).

Yes, you may have a title where you now are, but the world is turned upside down.

There are similar problems going the other way, one of the reasons entrepreneurial types tend to become serial entrepreneurs rather than stay with their start up, especially when it is acquired by a much larger firm.

So, does this mean that you should never try to cross the line?

Not at all. What it does mean is that you should do so knowingly, and with the supports you need in place.

The reason this matters, first of all, is that more and more of us find ourselves needing to cross over to self-employment, start up life, or (less commonly) going to an organization that has retained its fluidity. In today’s (and tomorrow’s) job market, crashing and burning is not an option.

So the person looking at crossing over needs support. Advisors who can counsel them on the challenges, be a place to bring their work experiences for advice, help them shift their mental gears from a rigid (and thus knowable) world to a world filled with unknowns.

Undertaking your diligence program, in other words, isn’t about avoiding being forced into a surprise change, or even about making a change. Yes, it is those things. But it’s also about succeeding once you’re underway in a new situation.