why does negativity take over your thoughts more than happiness?

Question: why does negativity take over your thoughts more than happiness?
- Keywords:
  happiness,
  negativity,
  thought
Asked by 553mutg26 to Emma, Monica, Sebastian, Sinead, Thomas on 14 Nov 2016.
- Emma Roycroft answered on 14 Nov 2016:
  
  I think we are naturally prone to stress and worry about things going wrong. However, we have to make an effort to be thankful for the good things in our lives and unplug ourselves from the negative thoughts. Some people can’t do that, and it could be due to imbalances of chemicals in their brains. It is not my are of research, and is still poorly understood. Maybe you could work on this!
- Sebastian Gornik answered on 14 Nov 2016:
  
  In evolution, it was more important to learn to avoid bad times and bad things that could potentially kill you, this is why we worry more then we think about the good times!

Question: why does negativity take over your thoughts more than happiness?