When you stop paying attention to your negative emotions and just masking them with positives you could cause huge problems down the road. 

We are so into the self help books that tell us to be positive all the time.  Don’t hear what I am not telling you.  I am all about being positive in every situation.  The key is not to suppress the negative emotions that come.  You need to recognize them as they are coming and figure out how to learn from it.

Negative emotions have similar affects as failure.  You learn the most from failure but most people don’t want to experience it.  Negative emotions are a part of growing as a person and if you try mask them with positive emotions you will never learn anything.

Be optimistic in life but learn from negative emotions and things that happen.

A great article related to this is at Personal Growth Map.