Monkey, I really wish I had no clue what you were talking about, but I know this autopilot reaction all too well. In spite of all evidence to the contrary, my brain keeps pulling me back to that 'absurd' place. Until we can get rid of it, I think the most important thing is to make sure it doesn't turn into a self fulfilling prophecy when it comes to how the other person feels about us.
I'm glad you are catching yourself in the act...I think that's a prerequisite to changing it.