I'm totally ignorant of lots of things. And if I tried to do stuff in those domains, it would probably be a shame that I didn't know what had been done before (though I concede there's some chance that it might not be).
That same bewilderment might not happen if you read about all the amazing things that already exist before you even get started. If you read or see too much of what's already been done first, you might just end up feeling starting from scratch is boring, because it isn't as interesting as the more advanced stuff other people had already done.
This is pretty much my feeling in every side project idea I've thought up :D