it can also be a matter of what we take note of. I read recently in a book the idea of going to an orchestra concert and trying to just focus on the violin players the whole time. yeah theres a ton else going on but one just pay an awful lot of attention tot he violin players only.
I could drive down the road and notice every place that sells booze and not really notice much else despite the fact there mighta been a zillion other things to see.
i sat at thanksgiving dinner for example a couple years ago and was basicly consumed with a fixation on the wine at the table and who was drinkign it and how much was left etc... who knows what i missed out on becuase I was busy obsessing over the wine.