If there's anything I learnt from discussing my ideas with family, friends and others, it's that finding the right people to bounce your ideas off of is crucial.
I think Will Wright (famous game designer) described this phenomenon well. To paraphrase, every time he would try to describe a new game to someone else, that person would create a game design in their head and play their game in their head, and then tell you what their thinking is. However, what you want, is someone to play _your design_ in their head. That's very hard to do without a prototype. For example, basically everyone told him that idea for The Sims is terrible. Only when they played his game did they see the light.
I think Will Wright (famous game designer) described this phenomenon well. To paraphrase, every time he would try to describe a new game to someone else, that person would create a game design in their head and play their game in their head, and then tell you what their thinking is. However, what you want, is someone to play _your design_ in their head. That's very hard to do without a prototype. For example, basically everyone told him that idea for The Sims is terrible. Only when they played his game did they see the light.