Ah, I see many of you have met my former roommate. She knew EVERYTHING. I mentioned the Language Debate, but it's worth repeating here. As background, I have bachelor's degrees in French and Spanish language, but wasn't raised speaking either, so I learned both from nothing. Roommate at that time was working towards a bachelor's in biochemistry (and she was quite smart, just not about EVERYTHING) and had taken a grand total of one year of Spanish in college, and no French at all. We once had a conversation that went pretty much like this.
Me: I found French easier to learn really. Spanish and all its darn tenses!
Captain Know-It-All: No, Spanish is easier.
Me: Oh, I know some people think Spanish is easier, but for me French was.
Captain KIA: No. SPANISH is easier.
Me: ...Compared to what? You've never studied any other language.
Captain KIA: Spanish is just easier.
Okay. ::walks away::
Then there was the time that she insisted that "mountain lions" and "cougars" were two species separate and apart. When I pointed out that they're just two different names for the same animal (having grown up in an area where those critters are still a definite part of the ecosystem, I know a bit about them. Mostly how to avoid them, because they are scary
), she informed me that SHE studied BIOLOGY therefore she KNEW WHAT SHE WAS TALKING ABOUT. Righty-o, then.
That's not even going into how she used to glare at me and make PA comments whenever I ate meat in her presence. Because she was a vegetarian, therefore she should not be exposed to me eating my pork chop at our shared dining room table.
I am SO thankful for the roommate I have now, who is awesome.