Somewhat funnily, Simon's frictions with Groening allegedly made their way into one of the more famous early season episodes: The Flaming Moe. Apparently that episode was written to reflect the pair's relationship, at least according to Simpsons writer Mike Reiss, and the plot drew parallels to Simon's status as the "real creator" of the show, as opposed to the guy who got all the credit. Whether Simon was aware of that allusion remains to be seen, though he did once concede that it "may be true" in an interview. It's an interesting theory at least.
