18. Melinda Clarke as Julie Cooper-Nichol on The O.C.
During the Fox show's four-year run, Julie Cooper wasn't just one type of bad mother to her two teenage daughters—she was every type. Materialistic socialite who abandons her husband as soon as he gets into financial trouble? Check. Money-grubbing trophy wife who marries a much older man for his multi-millions? Done, and by the end of the first season. Cougar? Indeed, since she had an affair with her daughter's long-time, but by then ex, boyfriend.
Julie covered the promiscuous divorcee thing in the series' entire back half; she also threatend to ship her daughters off to boarding school multiple times. For all her trifeness, though, Julie was a walking soap opera the audience loved to watch. It's crazy to remember she wasn't even a main cast member when the show first started.