Daffy was the first real "Looney" character of Looney Tunes," explains film critic Leonard Maltin in this explanation of who Daffy Duck was in the world of cartoons. Other artists and directors (i.e. Chuck Jones, who did many great cartoons) give a quick comment on how crazy Daffy was.
An interesting note was an explanation of why Daffy "hated" Bugs. It's all ego, folks, about jealousy and perhaps the poor Duck not ever getting his due, especially when Bugs became "number one." I also was glad to see a plug for one of my all-time favorite cartoons: "Duck Amuck" (which Jones directed).
Although very short in length, but I found this "documentary" very interesting. It can be found on Looney Tunes Golden Collection Vol. 1.