When I was younger, I used to daydream and every now and then I would get in trouble for it. Usually, the people who thought I should be doing more productive things were adults who, I believed had lost their ability to dream. Dreamers are important for our society without them we would not move forward. However, dreaming is also important for our own future. I am a believer that we are the authors of our own stories and as such we have an obligation to imagine the best future for ourselves to dream of happiness, abundance, health, romance, or friendship.
If I were an artist instead of a writer, I would believe that we are the painters of our own canvas. If I were a carpenter, I would believe that we are the architects of our own future. Whatever metaphor you choose to live your life through, you need to dream. When you create your dreams, they tend to become your reality if you work hard and keep your dream alive. These dreams of a good future, work because they are in your best interest and for the most part, you don't question the validity of these dreams.
But sometimes when you dream of a specific house, employer, love interest, deadline, dollar amount, or diet fad, you question if these dreams are in your best interests and often don't work as hard to make them come true. Here is a thought, keep your "end results" general. Everything else is just a how.