Most people have heard the cliché "It's funny because it's true." As with many clichés, it turns out there is some validity to the expression, as there is an entire book written on the subject -- the aptly titled Truth in Comedy by Del Close and Charna Halpern.
Truth in Comedy's core insight is that meaningful and memorable comedy takes more than just cheap jokes, and has to have an underlying truth supporting it. While the book focuses on improvisational comedy, this insight is extremely relevant for anyone making entertainment. In fact, you can find similar lessons that have been passed down by writers, actors, musicians, film makers, and fine artists.