Don't complicate things

Why is it that some people like to complicate things? If you are told that happiness is the meaning and the purpose of life then start being happy, look for ways to be happy, follow the path to happiness. When i read in a book that a friend i had gave to me that says that the purpose of life is to be happy i knew what to do, i didn't complicate what the book says, i started taking action and finding ways to be happy.