The first few days or weeks in a new role and with a new organization are the most critical. In his excellent book, The

First 90 Days, Michael Watkins stresses the importance of getting off to the right start:

"...transitions are critical times when small differences in your actions can have disproportionate impacts on results....Failure to create momentum during the first few months virtually guarantees an uphill battle for the rest of your tenure in the job."

And more specifically:

"The actions you take during the first three months in a new job will largely determine whether you succeed or fail."

Over the years we've been called in more than once to "rescue" a company from a previous hiring decision gone awry. We've seen issues and incidents that you wouldn't believe - ones that even a crate load of Watkins' books wouldn't ameliorate. Situations where it became clear, within a matter of weeks or even days, that a new member of leadership had committed serious errors in judgment, made significant missteps, or otherwise had rendered their position untenable. Here are five memorable ones we've heard of:

1. Set new rules to serve yourself. "Company X" hired a new Chief Human Resources Officer, who wowed them during his interviews with the executive leadership team. During his first week, however, the Chief Executive Officer was a bit surprised to find one of the CHRO's first acts was to institute a brand new flex-time/telecommuting policy. The CEO was even more surprised when, during his second week, the CHRO became the first executive to make use of the new policy, spending half the week working from home. When this continued on into the third and fourth weeks, the CEO knew she had made a bad hire.

2. Spare no expense and take it easy! We've heard of a new executive - hired to lead a frugal company through restructuring and downsizing - who upon arrival, had two eye-popping, state-of-the art, widescreen plasma TVs installed in his office; another who, in the middle of her very first day, disappeared to the gym for a three hour workout; and another who begged the question - how soon is too soon to request your first vacation? Our guess? Spontaneously deciding to take two weeks off after your third week, as he did, doesn't bode well.

3. Shirk from reasonable responsibilities. In another amazing case, a soon-to-be client brought onboard a new Chief Operating Officer (referred by a member of their Board) who seemed to get off to a flying start. It became obvious, however, that there was severe miscommunication during the interview process when the CEO requested the COO join him on an extended trip to the company's European offices, and the COO replied that he was unwilling to travel for more than three days out of the week, and, in any case, didn't have a passport. We got the call for "help" the next day.

4. Overly integrate your personal and work life. We applaud companies that provide proximate daycare and other family-friendly arrangements to employees. However, when a new executive arrived on the second day with three kids in tow (without any previous notification, and in an open-plan work area), the writing was on the wall - literally, with crayon!

5. Undercommunicate. We knew of a top-notch marketing executive who racked up a laudable series of accomplishments immediately after joining a high-growth, global enterprise. The problem? Her CEO knew nothing about it and, in fact, went days without being able to connect with her - eventually learning she had traveled overseas to secure a critical strategic partnership. It's not just about what you accomplish, but "how" you go about doing so.

Certainly, those are extraordinary types of behavior. While those examples are obvious, how do top executives ensure they avoid more common mistakes and get off to the best possible start? Watkins himself believes:

"Your success or failure rests, to no small degree, on your ability to diagnose your situation, identify its characteristic challenges and opportunities, and fashion promising action plans."

And he underscores the key, immediate, priorities:

"...promote yourself, match strategy to your situation, accelerate your learning, secure early wins, [and] create coalitions...."

Beyond the outlier examples described above, where we have seen many well-accomplished executives stumble is in doing the exact opposite of what Watkins prescribes. Instead, joining an organization with a personal, preconceived, agenda or plan, and then attempting to execute without performing a formative, thorough assessment or diagnosis. There is no such thing as one-size-fits-all, and a "best practice" at Company A might prove culturally fatal when implemented at Company B. The best executives spend their initial time with an organization as if they were a consultant, seeking to listen, understand, and synthesize - conducting a deep investigation of the facts before them, surveying the landscape, and otherwise ascertaining as complete a picture as practicable before developing and executing an action plan.

Simple concepts that are worth remembering for any executive joining a new organization...in addition to waiting a few months before requesting that 2-week vacation.