As with her son, Susanne is very depressed most of the time, as her husband Hank does nothing but mow his lawn, and not interact with her and the kids more.
She tries to hide this by acting friendly and gleeful.
Though not as overprotective as her husband, she does follow most of her husband's advice and makes sure that her children behave as much as possible.
She also happens to be very desperate for a new husband, as shown with her behavior around Marvin, who she constantly flirts with and tries to win over.
Speaking style
Soft, sing-song cadence with quick leaps between cheer and sorrow; uses tentative optimism mixed with subtle sarcasm; occasionally speaks in short, whispered asides to herself