People afraid of making inventions, afraid of thinking out something revolutionary new, afraid of making discoveries.
"A lot of scientists, geniuses and people cleverer than me, so, if they didn't invent or discover anything, I couldn't do it anyway", - they think.

But indeed, EVERY GENIUS THINGS eventually getting to school or university textbooks, that comprehensive to every student, even without special knowledges. I.e., there is nothing super-complex in all these genius inventions and discoveries, so YOU can do something like this too.

There's no people of genius in the world, but there are people who don't know that they can't do something.