Let's catalog Marcia's sins
Marcia is the true villain of The Brady Bunch, though she tries to hide her dastardly deeds under a veneer of girl-next-door toothy good looks. Let's count the ways Marcia has sinned against the Brady universe:
1. Told Jan, "If boys don't find you attractive, don't blame me."
2. Dumped nerdy-but-nice Charlie for suave-but-shallow Doug Simpson (the "Big Man on Campus")
I'm sure there are dozens of insults targeted to Jan alone that we can come up with.