An inflated ego is not a highly appreciated attribute in a person, so much so that s/he might be annoying or disliked no matter if it's case of egotism or egoism.
However, an overly deflated ego can also be detrimental to one's success or psychological well-being, especially in modern day society where it's often important to stick out from the crowd and show yourself in the best possible light.
Is there a word, noun or adjective, that describes a person who's ego is so low that it might be detrimental for his/her own best? Please note that I am not referring to low self-esteem, or being insecure.
Speaking of low ego, the word humility comes to mind, but to my ears, it's a positive attribute so I don't think it captures the idea entirely.