Opens Friday

Melissa McCarthy can be very funny. Click around online for the gag reel from Bridesmaids or This is 40 to see what a formidable improv comic she is.

Unfortunately, the first few scenes of TAMMY, McCarthy’s first headlining comedy, come off surprisingly lame. An “uh-oh” feeling hangs in the air. Then the film gets much, much worse.

Filmed largely in North Carolina, Tammy is a witless odd-couple road movie starring McCarthy as a fast-food clerk who loses her car, her husband and her job in a single afternoon. With nothing else to lose, she sets out with her hard-drinking grandma (poor Susan Sarandon) to start anew, or visit Niagara Falls, or something.

Written by McCarthy and her husband Ben Falcone, who also directs, the story goes nowhere at all, slowly and in circles. What’s truly perplexing is that there are no good jokes in the entire script. Well, there’s one, about Boz Scaggs. McCarthy’s incessant profane riffing produces an occasional laugh, but that’s just an issue of quantity.

Also victimized in this year’s most disposable comedy: Kathy Bates, Toni Collette, Allison Janney and a very embarrassed-looking Mark Duplass. Ugh, what a waste.