When I was a kid I was a huge fan of Calvin and Hobbes and it drove me crazy there were no cartoons, video games or merch. I even sketched out a design document for a C&H game where Calvin's various alter egos were used as power ups.
Then I read the 10th anniversary book where Watterson lays out the reasons why he never licensed the character out...and it made perfect sense to me. I always appreciated Watterson sticking to his guns and I think it's one of the reasons the strip remains beloved.