What I mean by basing your identity about work is that your personality, your life, your social circles, etc etc is based around work. Is like someone basing their identity on their sexual orientation, or the sports club they support. Their work is their life, almost a cult like following, and use that work for making others part of that circle (think cultural fit shit, about people not wanting to hire/promote people because they don't hang around for friday evening beer social hour, or in a kind of upper management thing, not wanting to hire people that don't play golf)