Step 1 : Introduction to the question "Which movie star's mannerisms inspired the nonchalant attitude of Bugs Bunny?"
...The Bugs Bunny we all know and love began to take shape in 1940 on movie screens across the U.S. He appeared in a short film in 1940 called "A Wild Hare." Bugs' mannerisms were partially inspired by the movie legend Clark Gable. A scene in the movie "It Happened One Night" showed Gable, in his nonchalant manner, eating carrots while leaning on a fence. After several years of tinkering, the Bugs Bunny of legend solidified on the screen, with the iconic Mel Blanc providing the voice. Source: MentalFloss.com