"Four Regrettings" saw four characters � Homer and Marge Simpson, Mr. Burns and news anchor Kent Brockman � look back on their lives and consider the questionable choices they've made. Mr. Burns let the love of his life slip away because he couldn't take her advice to think about others for five minutes a day. Homer sold all of his Apple stock to buy a bowling ball. Kent Brockman didn't follow his former co-anchor in trading local news for the big time. And Marge Simpson wonders if perhaps she is responsible for son Bart's rebellious streak, due to � of all things � an unexplained hankering for the music and imagery of KISS during her pregnancy.

This last one was such a bizarre twist, that Radio.com reached out to Simpsons Executive Producer Al Jean to ask about its origins. While Jean didn't come up with the idea, he felt compelled to go along with it: "As a corporal in the KISS Army, I could only obey."

"[Director] Jim Brooks suggested that Marge was hooked on KISS music when she was pregnant, and that she worried it had made Bart what he was," Jean said.

Two songs from the KISS catalog made the episode, both of which had significance to Jean: "We used 'Detroit Rock City' and 'Christine Sixteen,' two songs that have special meaning for me (I am from Detroit, and left there for college at 16). As Marge said, 'Anything from Love Gun' would be great."