I'm laughing inside because I know several music theory and performance majors here at school that would balk at the idea that all these "obviously very different" genres could be the same thing. Alternative and indie? Those are clearly two different genres. How could you even think to confuse them?!

Seriously, when they tell me about a band I should listen to, I ask them to describe it, and after they do I have even less of an idea of how they might sound than I did from just hearing their name.