Yes working hard and competent is the bulk of it. But we've met people like that we simply wouldn't bond with. Culture fit is hugely important, and if you hire a cultural misfit, it's much more difficult to fire them.
Curb your hubris and start treating people like human beings. I've worked for a number of "world changing" startups managed by 20-something year olds like you and the fact that it always devolved into a high school popularity contest made me sick to my stomach.