I've seen Steve Buscemi and John Goodman in the same movie not directed by the Coens
Which film would that be then? And no, I'm not counting Monsters Inc/Monsters University as they are not "seen" in that.
Witty dialogue can be found in films by other writer directors, as well as weird settings and plot devices.
Er, yes. As can roads! I wasn't saying these things were unique to their films. That's why it's not called "8 things that can only be found in Coen brothers films". You've missed the point here.
One thing this guy left out that I haven't seen used in almost all of their movies is the ambient background sound of a water heater growling inside a house or large building
Good one.

Not really.
I've seen Steve Buscemi and John Goodman in the same movie not directed by the Coens, and Frances McDormand has been in a slew of non-Coen related films as well. Witty dialogue can be found in films by other writer directors, as well as weird settings and plot devices.
One thing this guy left out that I haven't seen used in almost all of their movies is the ambient background sound of a water heater growling inside a house or large building. It's heard in Blood Simple, Barton Fink, Hudsucker, Big Lebowski, Man who Wasn't There, O' Brother, The Ladykillers, Miller's Crossing, and No Country (I think there are more).