Why did Bill Watterson quit making comics?

Answer 1

Bill Watterson did not set out to make Calvin & Hobbes a successful comic strip; he just drew comics because he was interested in them. In fact, he's stated many times that he regrets having made such a popular strip. In the ten years of making Calvin & Hobbes, Watterson eventually achieved every goal he had set out for himself at the beginning, and he was ready to move on to other interests of his, like painting and music.

Sure, it's a shame that Calvin & Hobbes is gone, but think of it like this; it's better that he stopped making Calvin & Hobbes when he had lost interest in it than if he continued drawing the strip without any interest in it.