Every great invention, every magnificent work of art, every brilliant accomplishment began with an idea. There is no limit to how far an idea can take you. And yet, the idea alone is not enough.
Ideas are worthless without execution.
You've probably had hundreds or even thousands of workable ideas. And the only ones which ever amounted to anything, were the ones you acted upon. Ideas create value when action is invested in them. In fact, the more you act on your ideas, the better those ideas become. If you never have to act on your ideas, you don't care if they're realistic or not.