There's a pervasive, logical fallacy out there in startup land. Propagated by a Steve Jobs quote and entrepreneurs in denial, it is the fallacy that customers don't know what they want until you show it to them. Of course, the mass market doesn't know what it wants until you show them, but early adopters do. Logically, they must know.
A good point worth making more than once: if you are convinced that your idea is evidently brilliant, but you can't get any customer validation for it, you are wrong.
Going into denial, failing to accept that you're wrong, won't make you right: it'll just make you poorer. Having a vision is essential. Having tunnel vision is deadly.
It is important to get some market validation for your ideas, especially if you think they don't need validation, because they're obviously valid: that's the time when you're most in danger of getting it all wrong and flattening yourself on the ground like an egg fallen off a high shelf.