(Strip Number 5106, Original Publication Date: 20 March 1989)
Panel 1: Having noticed that Elly is cooking that one meal that she always serves when people are coming over, Mike asks Elly who they're having over for dinner. She tells him that it's Phil and Georgia because she's not smart enough to qualify that with a kinship term like she should.
Panel 2: She sets up by the punchline by telling him that she wants him to watch his table manners and be on his best behaviour.
Panel 3: When Mike asks her why they're standing on ceremony because they're only having relatives over, Elly looks gobsmacked for a second.
Panel 4: Her response is to bellow that they have to start somewhere.
Summary: The "somewhere" Elly should have started is, of course, with Mike and Liz themselves. She'll deny it to her last ounce of strength because her kids aren't "supposed" to pick up her bad habits but Elly's default assumption that it doesn't matter if she'd repulse a select committee of Klingons with her eating habits because it's "only" the kids she's eating around and she doesn't have to impress THEM is most of why they grow up thinking that the nasty, smacky, messy, gobbly way she eats is normal.