That is true. I mean, this is pretty normal after all considering we are social creatures. We tend to listen more to the people we like.
Sure, that means that someone can occupy a certain position without having the skills needed just because he is likeable. He then can go and fuck things up really due to him not knowing what the hell he is doing but hey...the world ain't perfect.
Yes a person can, based on the power other people assign them. We can blame him for being a dick or whatever, but we are also the ones that put them there through our own action or inaction.