The reason for our feelings

Why do negative feelings and emotions exist? Positive feelings and emotions were "selected" by Evolution because they produced appropriate behaviour in us humans for our perpetuation as living beings on our planet Earth. But what about negative feelings and emotions? Incredible as it may seem, they were also essential to our survival as a species. We wouldn't be able to survive the often hostile conditions of our habitats if we were 100 per cent passive, possessing only positive feelings. This book presents many scientific facts as well as my own ideas on the subject, and is open-ended because it really is very controversial, something still to be further explored by Neuroscience in conjunction with related sciences.