Competency

Joining a new company is like going back to class 1. When you leave the previous place, you are at a certain position and (usually) respected and known for your performance in a certain area (at least). You have knowledge of the history and present plans of different projects. You have seen them grow, else have beent here for some time to be totally aware of them. In short, you have certain competence on which you base yourself and therefore achieve success.

On joining a new compnay however, you take with you the knowledge of what do do with the competence, but not the competence per se. You start from scratch. You have to start off with learning the projects, at their already developed stage. The worst part is, you might have come from graduation level, and are expected to behave like a post doc, while you have the competence of a grade 5 student.