(Strip Number 900, Original Publication Date, 26 July 1985)
Panel 1: As she puts Mike to bed, Elly does that eyes-closed, back-turned-to-him thing when she tells Michael to ask Lawrence if he wants the bed or the air mattress.
Panel 2: Mike whines about how he should sleep in his own bed. Since Elly is all about appearances, she tells him that it's polite to offer a guest your bed when she really means that she's ordering Mike to sleep on the air mattress.
Panel 3: Like the Patterson he is, he responds by unhinging his jaw and yelling "I don't wanna be polite — I wanna be COMFORTABLE!"
Panel 4: When Elly glares at him as if to thought-bubble her threat of physical harm, Mike sheepishly states that he'll be polite.
Summary: No wonder the Patterson children grow up to be so ill-mannered and grasping; they're forced into it by associating gracious behaviour with being threatened.