Has happened a half dozen times.
Get a new cool idea you can't get out of your head, get a burr up your ass, and go register domain, and start development with or without the business model, or plan. Just the idea in your head. Next thing you know life throw's a curve, the adreniline wears off, and idea stagnates.
If it's not that, then it's the time factor. Something else comes up, or whatever. Some of them are decent ideas, which I will keep to myself.
