The decision process, something that we do hundreds of times a day, seems so straight-forward and natural but involves some really complex internal processes. Making a decision is a delightful orchestration of mental processing, short-term memory, long-term memory and some far reaching chemical processes.
Interesting tidbit one: The more we think, the less we feel. Studies have shown that when people know how expensive something is, their enjoyment of it increases. However, when participating in blind taste tests (without knowing the price) they often enjoy the cheaper items more.
Interesting tidbit two: The best way to make complex decisions is to study them, then distract yourself for a while (to let your subconscious process the information) then, suddenly, be forced to make a decision. This allows your intuition to pop out the results of your subconscious processing.