Happiness is often derived from your expectations. Have high hopes, high expectations and you are setting yourself up for disappointment. Outcomes are at times outside of your control, but your expectations are always within your control. If you want to be happy, lower your expectations. 

Humans think that they are better/stronger/faster than they really are - that is just our nature. This leads to a vicious cycle of most people over promising and underdelivering - you don't want to be one of those people. Instead, have realistic expectations of what your employees, investors, friends, family and most importantly you will  be able to deliver on. 

You are the master of your destiny and you shouldn't EXPECT the universe, an investor, a supplier, a friend or anyone else to simply give you what you expect or feel you deserve. It is  on you - don't expect any help. 

Only when you admit this cold hard truth will you award yourself the mental position necessary to move forward and be successful.