Mine is rejection. I am vigilant beyond belief because I never want to be surprised by someone leaving. I analyze and over analyze everything, presenting myself with every possible scenario so I can mentally prepare for everything. The one where a person leaves, like my father did when I was 4, is the one I always settle on as the most likely eventuality. I am constantly watching for the signs and ready to cut and run at the drop of a hat.
I just don't know what to replace this mental garbage with.