Movie: Where'd you go, Bernadette? (Where'd You Go, Bernadette)

You've heard that the brain over time, everything depreciates. For example, you gave the diamond necklace. You open a gift and you like it. First you're happy, the next day, too, but a little less. A year later, you look at him and say, "just Think, junk.." And you know why the brain does that? For the sake of survival, you should be ready to new experiences not to miss a signal of danger. However, it would be great to cancel it? After all, saber-toothed tiger already precisely you will not verigny. I think this is a constructive defect, if the brain of a default survival and danger, not joy and gratitude.