An idea has been occupying your mind round the clock. Should you just ignore it or consider it seriously?
When an idea bothers you to a high level start validating the idea. See whether it really solves the existing problem or gives any ease in doing current process. Idea validation phase will involve a lot of market research. If your idea is totally out of the box take into consideration the acceptance factor too. To make users accept and like it prepare a strategy how would you market your product. It may take time for your product to acquire the market or even to be accepted. Just like the 'Free Hugs' campaign by Juan Mann....but eventually it did spread wide!
If all the factors are working in your idea's favor- valid, worthwhile, acceptable and rest of prerequisites also satisfied then take the idea to next phase....next to simply thinking about it! And once you step into the next phase do not be skeptical or pessimist about it. The said statement is equally applicable in such case- 'Keep your eyes wide open before marriage, half shut afterwards'!