It’s not what you think — I cover this topic in my book Neuro Web Design: What makes them click? You like to think that when you make a decision you have carefully and logically weighed all the relevant factors. In the case of the TV, you have considered the size of TV that works best in your room, the brand that you have read is the most reliable, the competitive price, whether you should get blu-ray, etc etc. But the research on decision-making, especially the recent research, shows that although you want to think that your decision-making is a conscious, deliberate process, it’s not. Most decisions are made through unconscious mental processing.