Peanuts by Charles Schulz for February 06, 1957
Linus: Look, Lucy...Look how nice I colored in my color-book.. Lucy: ARE YOU CRAZY? Do you want to be frustrated and inhibited for the rest of your life? GOOD GRIEF!! Lucy: Don't you know that if you color inside the lines in a color-book, you'll become inhibited?! Lucy: Worse yet, you're liable to become good at it, and end up as a commercial artist! Linus: Horrors!