The genius of the gag was anticipation. What kind of creature could be born from that gene pool? The audience imagined a female Liam: greasy hair, a lazy eye, and a thirst for sour milk. We weren't ready for the truth. The wedding of Liam and Maureen Ponderosa (RIP) is a bloodbath of Oedipal chaos. In the chaos, a new McPoyle emerges from the Paddy’s Pub bathroom. She’s tall. She’s wearing a damp beige bathrobe. And she has… a mustache .
In a show about the worst people in Philadelphia, Margaret McPoyle might be the worst. Not because she’s evil. But because she’s patient. the mcpoyles sister
She’s also a rare example of It’s Always Sunny playing the long game. The sister wasn’t a one-off gag. She was a carefully aged threat, left to ferment like an open jug of dairy on a radiator. The genius of the gag was anticipation