You might be surprised to learn that failure isn’t the biggest enemy of success.  In fact, failure is very much a part of success, they are like two squabbling siblings who would defend each other against the world.  No, the biggest enemies of success are apathy and negativity.
It’s all too easy to come up with reasons something might not work:  it’s too much, there’s too little time, it won’t be fun, it needs more thought, it’s the wrong time, it may go wrong, we may look stupid, we may fail.  Maybe when X has happened or maybe some time in the future would be a better idea?  That’s just kicking a long ball with no intention of every running after it.
We can all be guilty of this in our lives, it’s a natural state to be negative.  Illnesses like depression make it even harder (and I tip my hat to anyone who has to battle that disease because it’s sometimes physically impossible to be positive).  But if you have any hope of being successful, whether it be writing a book or keeping bees, you have to be acutely aware of negativity and do your best to fight it.  The older I get, the more I see that the people who generally succeed are those that are positive (sometimes through the haze of depression), a little crazy and have had some spectacular failures.