Melissa, you can do so much better than this. (Warner Bros)

The Reelist is a column featuring Kristen Page-Kirby’s musings on movies. For Washington Post film critic Michael O’Sullivan’s review of “Life of the Party,” click here.

Here’s the good thing about “Life of the Party”: You don’t have to worry about missing anything if you go pee, because you already know what’s going to happen!

(OK, there’s one surprising moment. ONE. But don’t spend the money to find out what it is. Just email me and I’ll tell you.)

The plot goes like this: Deanna (Melissa McCarthy, who wrote the script with director and husband Ben Falcone) has been married for 23 years. Her husband (Matt Walsh) suddenly declares he wants a divorce. Deanna, who had dropped out of college with a year to go, decides to go back — at the same college her daughter attends! Isn’t that CRAZY?!

The story continues to be as predictable as a big predictable thing. Deanna is embraced by her daughter’s friends, all members of an appropriately diverse sorority with a way nicer house than sororities ever have. There is a makeover. There is a dance-off where Deanna is (gasp!) much better than expected. Everyone learns to be confident in themselves. (There was not, however, a car wash. I was expecting a car wash.)

Melissa McCarthy is very funny — just not in this movie. The scene in “Bridesmaids” with her driving a van full of puppies will never not make me laugh. She was great in “Spy” and the underrated “The Heat.” By God, was she good in “Gilmore Girls.” She’s picked her share of stinkers, but find me an actor who doesn’t have a “Tammy” in their past (that and “The Boss” were also directed and co-written by Falcone. So … maybe don’t work with him anymore, as awkward as that may make dinnertime conversation).

McCarthy is at her best when she’s allowed to commit and commit big. That doesn’t mean mugging for the camera, cinematically nudging the audience to look at how funny she is. It’s about playing a character absolutely seriously so that the humor feels more authentic. In “Life of the Party,” Deanna is an absurd character — would anyone actually wear a college sweater that looks like Liberace got ahold of a double espresso and a BeDazzler and just went to town?

Granted, McCarthy’s character in “Bridesmaids” was also absurd. But McCarthy played her absolutely straight. Deanna is so poorly written, it’s like McCarthy has to convince the audience that humor is, in fact, happening. In contrast, Maya Rudolph — the actual life of this party — brings authenticity and subtlety to her portrayal of Deanna’s best friend. When she smuggles little bottles of wine to the racquetball court, she doesn’t make a big deal that she’s brought little bottles of wine to the racquetball court. She just holds one, letting the audience find the humor instead of shoving it in their faces.

There are a lot of funny women working today, and McCarthy is among the funniest. But like anyone else, for her to rise to the occasion she needs an occasion — and “Life of the Party” isn’t one. A thinly written character and an even thinner plot give McCarthy nothing to work with, so she has nowhere to go but mediocrity.

More Reelists from Kristen Page-Kirby

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Cowboy up: ‘The Rider’ and the pain of masculinity