Why does the brain mostly remember tragic, bad or embarassing memories instead of the happy ones

Question

Why does the brain mostly remember tragic, bad or embarassing memories instead of the happy ones

In: 4262

Answer 1

Because that is the stuff it needed to remember to stay alive. Really bad stuff (including loss of social support like in embarrassment) could have been a death sentence for us further down our evolutionary tree.

You remember the stuff that can kill you so you are VERY motivated to avoid it.