Vanity License Plate: Bunny's says LAPIN.
Verbal Tic: Fuckin' everybody.
Some editions of the BluRay include the "Mark It Dude" feature, which notes every instance of "Lebowski", "Dude", "Man", and "Fuck". The Dude says "Man" 147 times, that's like a lot, man.
Walter's "Shut the fuck up, Donny!":
Donny: They posted the next round for the tournament.
Walter: Shut the fuโ when're we playing?
Viewers Are Geniuses: Many examples. One prominent one is the joke about Saddam Hussein handing out bowling shoes in the dream sequence. Understanding the joke requires some knowledge of the first Gulf War, Arabic, and President Bush's well-known tendency for mispronouncing words.
Vitriolic Best Buds: The Dude and Walter are, to an outside observer, completely incompatible people who, true to form, spend most of their time loudly arguing with each other. However, they're practically inseparable. Same with Walter and Donny; Walter spends a lot of time browbeating and yelling at Donny yet is clearly cut up when Donny dies from a heart attack.