My muse thinks they are hilarous.
My ideas tend toward the bright shining moment -- or preferably, more than one -- that I can hook together. There's no reason, even why it has to be a very dramatic moment in the story. One story was triggered by reading a summary of a movie that mentions how the legendary hero's daughters meet him for the first time (while still children), and built up from there. Others with the notion of how to break a certain kind of magic in a nifty way -- notice that one doesn't even specify anything about the characters. A book of artwork that has a character appearing in a number of paintings -- obviously a journey. Or with a title. Nothing so broad as the overview. Indeed, many of them could appear in many different works, if only developed the right way. They need nuturing and additions, developing before and after, before it's clear what the over-archinig story is.
Or, I get ideas that are too abstract to be a story. A character reads the Tarot spreads, and the cards are always right about what happens next, and the character, by dint of interpretation, is always wrong. A traumatic event happens to a bunch of characters in the same way, and it's a formative experience for all of them, but every one claims a character trait, formed by it, that no one else does. Those generally need to hang out until they bump into another idea that fills in the details.
How-to-write books can be variable because of things like that.