For a training at work, I am reading "The 7 habits of highly effective people". I assume everybody in the world has already read this book, because whoever I talk to about this book says something like:"oh yes, I liked this or that advice that was given".
The first of the seven habits made me realize how I became such a disgruntled postdoc. This chapter of the book talks about proactive and reactive people, and how proactive people focus on their so-called "circle of influence": the things in life that you can influence, like problems at work that you can solve. Reactive people however, focus mostly on things in their "circle of concern": things that you cannot influence, but that do affect you, like the weather. As a postdoc it felt like my circle of concern was huge: there were so many things I felt were very difficult to influence, like circumstances in the lab, reviewers, the competitive job market, my inability to get grants funded, etc. I felt like my circle of influence was this tiny dot in a huge circle of concern.
After reading this part of the book, I think it is important to clearly distinguish the two, and - even as a post-doc with a huge circle of concern - to work on the things that you can influence, like figuring out what you want to do next and taking steps to go there. Also: writing and submitting manuscripts, applying for grants and considering to appeal rejections (although this may be more the pro-active playing field of PIs rather than postdocs).