geezus youre on fire today 
i just despise liars is all. Having had to deal with a methhead relative for years, you get pretty good at identifying the behaviors - and this fuck couldn't be more obvious.
The most common identifier, aside from the fantasy life they create, is how passionate they are about convincing others they ain't lying: Lots of "I swear to God," "On my mother's grave," "I'm being TOTALLY honest," "100% truth here," kinda stuff. Shit honest people never consider. Think of the most honest people you know: How much time and energy do they spend trying to convince you they're honest?
None, right? They ain't lying is why, so it never occurs to them they gotta convince you otherwise. Joon's a textbook case, embarrassingly obvious. I hate them the way you hate druggies, and they're often the same person. Case in point.