Why do dreams fail?

There are many reasons why dreams fail. They fail because the dream is just to far fetched to work, the person who thought of the idea is too lazy to do something with it, or the person who thought of the dream is put down by others saying that it is a dumb dream and will never happen. Most dreams are too far fetched so they can't be done, like in 5th grade I thought of a robot that will do your homework, but later I went over it and figured that it was a bad idea because the programing behind it would be too complex so I just gave up on it. Also in 1st grade I had a dream to become a scientist, but just 6 years later I wanted to be a video game designer because it was told that it was a terrible dream to be a scientist so I gave up on it. In both of theses there was ether a person saying that it was a bad idea or that dream was too complex that it just won't work. But there is still that fact that the person is just too lazy to actually do something about it. Over all, dreams fail for many reasons but in the end it really is up to you if your dream comes true or is forgotten in the dark corners of your mind.