Getting a Fixation
How often have you heard it said, often parents talking about a son or daughter, 'they have their mind set on it and there's no talking them out of it.' And how many of us, at one time or another, have had our mind set on something that defies rationality? You have your heart set on buying something but when you've bought it you wonder what you were thinking? Or you change jobs and afterwards wonder why? Even when more rational minds have tried to convince you, you were set on the idea.
I've mentioned before about the mind being 'flipped' into a different mode of thinking and also about Carlos Castaneda's ideas on realities operating at different frequencies of vibration. These phenomena are related. When we get stuck in an idea it's akin to being in a dream, we have (usually) no awareness that it is a dream but then we wake up. Similarly, when we get a fixation on an idea we finally wake up, and wonder what we were thinking.
I've also mentioned before that countries, or cultures, can have personalities in the way that individuals do. So, in this regard, the USA's fixation on invading Iraq fits this pattern. More staid minds such as the UN warned them against it, and now that they've achieved what they set out to do they are left wondering what they were thinking.