If you are a nice person, being someone's boss is one of the hardest things in the world.
Perhaps managing people is no easier when you're an asshat. I'm not sure. But it sure looks easier if you're the type of person who can bark orders without flinching.
For years, I believed that some of my best traits (I'm gentle, empathetic and trusting) prevented me from being the kind of manager who can earn authority and respect. I'm best one-on-one, and I'd rather orchestrate a sugar-and-caffeine-fueled-brainstorm session, than tell people what to do.
But this style (I'm finally here to tell you), makes an effective leader too.