Melissa McCarthy is a master of ostentation, as her comedy relies not on setups and punchlines, but on a signature brand of all-caps emotional—and often physical—aggression. But while it's been extensively advertised as an outrageous Fourth of July gut-buster, Tammy is a surprisingly unostentatious, downright modest product. Clocking in at a slight 96 minutes, Ben Falcone's film is an almost plotless doodle, with low stakes made even lower thanks to the bratty passivity of its titular antiheroine. Its laugh count is notably small as well, though to be fair, Falcone, who co-wrote the script with McCarthy, seems more interested in drama than comedy once the obligatory slapstick set pieces that dominate the first half of the film are out of the way.
Tammy is introduced like so many comedic protagonists before her, suffering a series of humiliating defeats (job lost, car totaled, husband caught cheating), and all in one morning. McCarthy always excels whenever her characters are overcome with anger and frustration, but these opening scenes lack spontaneity and wit; the actress's most compelling scene partner in the first 20 minutes is an unconscious deer. Once Tammy reaches rock-bottom, she's freed to embark on a foreseeably disastrous road trip with her alcoholic grandmother, Pearl (Susan Sarandon), though even this plot development feels like an easy out, a generic narrative skeleton that gives its two stars ample room and opportunity to improvise and bicker with each other en route to predetermined final destinations both geographic and narrative.
Tammy's terminal waywardness is the most interesting thing about it, and if McCarthy and Sarandon's antics aren't as uproarious as they would seem to promise on paper, it's not at the expense of watchability. There's a seductive casualness to the film's middle third, even as Tammy and Pearl drift from botched robberies to jail stints to an extravagant Fourth of July celebration at the estate of Pearl's cousin, Lenore (Kathy Bates), and her partner, Susanne (Sandra Oh). Each of these sequences feels stumbled-upon, surreally disconnected from the doddering film surrounding it, in a manner that better recalls the actual experience of a road trip than most on-the-road films. But this sense of amiable laxity sours with the inelegant mid-film introduction of semi-traumatic backstories for both Tammy and Pearl, a flagrant bid for sympathy that McCarthy and Sarandon have already won by nature of being inherently magnetic performers. The film comes to a screeching halt whenever it coarsely attempts to manufacture drama in this way. By insisting on having characters proclaim their pain, the filmmakers eliminate any element of surprise or uncertainty to Tammy and Pearl's relationship, or their individual emotional journeys—which resolve exactly as expected.
Despite the plentiful personalities on display within it, Tammy is too tepid as comedy and too contrived as drama for it to develop a true personality. It will likely be remembered best—in an anecdotal, name-that-film kind of way—for its all-star cast, from the bafflingly underused (Toni Collette, who stars as the neighbor who has an affair with Tammy's husband) to the bafflingly miscast (Allison Janney, playing Tammy's mother and Pearl's daughter, thus completing the most improbable matrilineal chain Hollywood has ever come up with). At least Bates, handed the plum role of a loud-mouthed lesbian arsonist, makes a valiant effort at cementing Tammy as some kind of future camp novelty; surely no one can claim the world is worse off now that footage exists of Bates conducting a Viking funeral for a jet ski. But considering Tammy's overall slightness, "novelty" is probably the best-possible legacy it could acquire.