In order to seem edgy, nearly every new TV comedy infuses itself with a sense of zaniness. Watching Weeds and The Big C last night, we saw one show do wacky right, and one do it horrendously wrong.

The two Showtime shows are meant to be companion pieces, both about mothers in a desperate situation who go to extremes to improve their lives and keep their families together. In the case of Weeds' Nancy Botwin, she deals drugs to support her bland, middle-class existence once her husband dies of a heart attack. On The Big C, Cathy Jamison tries to rectify her life now that she's been diagnosed with terminal cancer and is given a year to live. Other than that, the quality of the shows couldn't be more different. The Big C is a wonderful and emotionally effective new show whereas Weeds, well, it's just a sad, self-indulgent mess. It's like a clown that stopped being funny, so he put on more and more makeup to try to get the laughs back, but instead of laughing we're just sitting at home thinking, "That clown looks ridiculous. Remember when he used to be funny?"

In its first couple of seasons, Weeds was great because it did "wacky" with such aplomb. It took a common, everyday situation and gave it one wicked twist. Nancy had the same struggles as every other soccer mom, except she made the crazy choice to become a pot dealer. She was never a great person, but she was relatable, and you knew that she was trying to do what she thought was best. Now, she's just a loathsome, self-involved creature who says she cares about her kids, but worries more about her shoes and coffee drinks than her babies. In the fifth season, Nancy moved to Mexico and married a drug kingpin and then her son murdered his accomplice. Now they're on the run from the law and a Mexican drug cartel. And don't even get us started with the abortion doctor who was held hostage by her crazy Christian stalker brandishing a crossbow. It's just all too much!

Yeah, we get it, these antics are the inevitable result of Nancy's one bad decision to sell pot. When the show started, it was about subverting the cookie-cutter suburban lifestyle and its attendant ennui. Now it's just a series of outrageous circumstances the writers are trying to make as crazy as possible hoping we'll chuckle. We won't.

While The Big C isn't as laugh-out-loud funny as Weeds was in its heyday, it's a much more compelling show. It hits all the right wacky notes, taking the ordinary and giving it that little bit of spice that makes it absurd. Laura Linney's Cathy is close to her doctor, so close they go to brunch together. She cares about the kids she teaches, so much so she's paying one to lose weight. She has a horrible child, a childish husband, a bitchy neighbor, and a no-good brother, but they are all taken to the extreme for effect. Sure, not all of us have siblings who are willfully homeless ecological crusaders like Cathy's, but every family has a black sheep. That's how to do off-beat!

This sort of outrageous sitcom might just be a game of diminished returns, and even The Big C, now so promising, will fall into the trap that Weeds did, compounding itself with outlandish yuks until it is but a caricature of its noble self. But in the final scene of The Big C's pilot, when Cathy is sitting on her wine-stained couch in a giant hole dug for a pool and is talking to her neighbor's crippled dog, it is firing on all cylinders. Cathy starts to simultaneously laugh and cry about her situation, her impending death, and we love her. We love her for being there and we love her because she's there in the way we would want to be. She's bigger than life, she's over the top, she's wacky in just the right amount.