At an event recently a person asked if the purpose of our book, "Code To Joy:The 4-Step Solution to Unlocking Your Natural State of Happiness" was to achieve a permanent state of happiness. A fair question and not one we thought to address in our book.
While there may be a few people who are in a constant state of joy and bliss, I believe that the majority of us regular folks dealing with day-to-day life will experience ups and downs. We really notice feeling up when it's in contrast to feeling neutral, or even 'blah'. In that sense, our 'natural state of happiness' is not a perpetual state.
However, being in the fog of distress is certainly not natural, it's the dampening of our ablity to experience times of joy and even bliss. Some people have been unable to access a state of happiness due to depression or anxiety. Depressive and anxiety disorders will affect nearly 20% of the population in the US at sometime in their lives. But even more people will have extended periods of time where they are feeling below the neutral line but not have a clinical level of depression or anxiety.