I was thinking the very same thing, that of a crowd mentality. I tend to spot them more easily because the very same dynamics occur in the financial markets – the irrational exuberance thing. Euphoria breeds more euphoria and despair breeds more despair. With someone who is severely unbalanced like MrsHD, her emotional swings can be so powerful they drag you into them even when you know you are being dragged. I’ve experienced the same thing with my wife in the past. Looking back I thought, how in the h*ll did that happen and why did I let myself get dragged into it? Emotions can be very powerful things, until you decide they aren’t (yeah, I know, easier said than done).