Marge says they watch the same shows all the time, while Lisa says that the Itchy & Scratchy cartoons are just pasted together from pieces of old episodes (and pointing out that Ren and Stimpy do it all the time). This comment is a sly joke about the construction of this episode; the blackboard and couch gags are taken from other episodes, there are clips from past episodes, and the interstitials are actually clips from past episodes that feature the family members talking in the kitchen. These three aspects support the idea of this episode being a clip show to the extreme.
Bart's story about Lauradidn't end in heartbreak: she dumped Jimbo after he broke down crying over Moe threatening to stab him, and Laura said that if Bart were old enough, she would go out with him.
Lisa's story didn't either; she and Ralph became friends.
Homer mentions that Mindy became an alcoholic and lost her job at the plant after his time with her, but future episodes "Team Homer" and "The Twisted World of Marge Simpson" show Mindy as sober and working at the plant. Either Homer lied about what happened to her (whether intentionally or just parroting a rumor he heard) or Mindy went to rehab, got better, and got her job back.