We’ve done “I’m only 3 1⁄2 years old”. Where did “I like him…he’s silly!” come from? I Googled a bit to no avail.
First thing to pop up when I googled it was a Bugs Bunny cartoon, because of course.
Bugs Bunny for me too.
Here’s the first thing that popped up on Youtube. It was some little gremlin saying it about Bugs Bunny.
I did a quick search, but all I can find is that it was apparently Bob Clampett who first stole the radio catch phrase and put it in a cartoon (something he apparently liked to do). Other Warner Brothers animators used it later on, though. Nothing I found reveals the original source.
As noted, though, quite a few of the WB cartoons catchphrases were stolen from the radio – “Ohh, I wouldn’t say THAT now”, “Coming , Mother!” “_______, isn’t it!” (that one’s from Jerry Colonna), or any of these:
http://www.therobotsvoice.com/2013/10/looney_tunes_bugs_bunny_merrie_melodies_catchphras.php
That’s pretty good. Thanks!