For a number of years, I worked in a series of jobs that had me working for bosses who were, for lack of a better description, truly nasty people. They argued with co-workers, were unnecessarily and often accusatory, changing their minds such that the thing that you were doing right one day was wrong the next; more often than not, their arguing and accusations were public, done in front of departments or co-workers. This is especially disturbing behavior when one can't quite tell what will upset a supervisor, so I have learned not to be as proactive as I should, because such questions were historically more often than not reasons for disparagement.
Even as an adult, I struggle with shyness and a lack of self-confidence; even though it's been years since I worked for anyone who was truly inconsiderate or unkind, I still find myself wary of authority; it still takes me some time to trust co-workers. I don't gossip or talk about my co-workers - not good reasons for connectingwith co-workers anyway - and generally just keep to myself.
That's not always a good thing. There's something to be said for networking and chatting with one's co-workers, but I still have trouble making the jump, and I have to make a concerted effort to make eye contact and smile (instead of just looking down at my feet, which I have to admit is still my default mode).
I need to work on being more proactive and organized in some aspects of my work; I need to learn to try to connect with my boss (at least in one of my jobs) and engage her in conversation a bit more (difficult to do, because although she's never been unpleasant, she doesn't seem especially interested in talking to me).
Not every critique will automatically lead to dismissal from one's job, and logically I know this to be true, but it's been hard-wired into my head that there will not be any warning, that I will lose any one of my badly-needed jobs because of some aspect of my performance that I could have improved. Not everyone wants to see me fail - something I've witnessed at previous positions - so I have to just resolve to do a better, more thorough job in some situations.