Well, you either have a explicit hierarchy of people working on something, and then the people who are a part of the "top layer" can sometimes start to look dow

Well, you either have a explicit hierarchy of people working on something, and then the people who are a part of the "top layer" can sometimes start to look down on the ones who belong to the layer below, seeing them as less knowledgeable or not producing useful output. Sometimes that leads to people starting to close down into their current layer, and forms "us-vs-them" groups. Or, you have a implicit hierarchy and basically the same thing happen but the layers don't have names.