Tex Avery described the initial fan reaction to Bugs Bunny's iconic catchphrase, ''What's up Doc?''
Bugs Bunny, certified brat.

Look, we can't all be as cool as Bugs Bunny. That rabbit has a seriously chill demeanor. The good news is that with the lasting impact that Looney Tunes cartoons have on both the hearts and minds of viewers, Bugs Bunny will never be too far away. As fans, we are perpetual students, learning from him constantly.
Save for a select few shorts (we're looking at you, Tortoise Beats Hare), Bugs maintains a fairly unbothered energy. It's a quality we envy him for, and it's something that Warner Bros. animator Tex Avery felt was crucial.
"He was a smart-aleck, but he was casual about it," said Avery in The Great Cartoon Directors, written by Jeff Lenburg.
If you're blessed with a half-decent memory, you might remember that during Bugs' first appearance in the short A Wild Hare, he is face to face with Elmer Fudd's rifle. It's a situation that would be sure to cause a bit of panic, but Bugs remains cool as a cucumber. The reaction, along with the catchphrase, was a hit with the audience. Avery knew he had struck gold. With Bugs, anything was possible.
"The opening line in the first one [A Wild Hare] was 'Eh, What's up, Doc?'" said Avery. "And gee, it floored 'em! They expected the rabbit to scream, or anything but make a casual remark— here's a guy with a gun in his face! It got such a laugh that we said, 'Boy, we'll do that every chance we get.'"
