There's something about Jennifer

How has a brilliant comic actress managed to star in so many unfunny romcoms? As another Jennifer Aniston film gets panned, Ben Walsh leaps to her defence

Jennifer Aniston stars as Elinor Dashwood in Jane Austen's Sense and Sensibility ... no, of course she doesn't. Aniston doesn't do period drama. She is a defiantly modern, all-American actress; a tabloid favourite; one of the faces for L'Oréal and ... wait for it ... the woman who lost Brad Pitt to Angelina Jolie.

And it doesn't matter one jot how much worthy UN work Jolie does, most of us are still stubbornly Team Aniston. Why? Because she's so ordinary, that's why. So very ordinary and accessible with her engaging, genial comments like "I couldn't have found a better man than Brad. He still opens doors for me and brings me flowers. He's the sweetest goofball on the planet". Ouch. That has to hurt now.

The sleek, perma-tanned 40-year-old from Sherman Oaks, California, started out so deliciously perky, all glossy hair and clean teeth, as Rachel in the defiantly upbeat sitcom Friends, but Jennifer Aniston's face appears to become progressively more downcast in every film she appears in. She's morphing into a sort of female Buster Keaton. Her smile is growing fainter and her film choices – or the parts she is being offered – are getting steadily shoddier. The Independent's film critic, Anthony Quinn, described her latest one-star film, the unfortunately titled Love Happens, starring Aaron Eckhart, where Aniston plays an archery champion turned florist, as a "cry-baby romantic drama" in which "Aniston just about passes muster". The Times went further, saying, "The formula they've come up with is to remove all the comedy, which is a bold choice." The Scotsman go further still, "Love Happens ... there's just not much evidence of it in this dreary romantic drama." Previous Aniston films have been described as follows: "From the start it misfires on all cylinders" (The Observer on Rumour Has It); "There is something wildly odd about a film that measures human happiness with the whims of a dog (The Times on Marley & Me); and "A heavy-handed and charmless psychological thriller" (The Guardian on Derailed).

Aniston began her movie career relatively late (let's not count the abysmal 1992 horror Leprechaun) at the age of 27 in 1996 with Edward Burns's winning She's the One and Tiffanie DeBartolo's less winning Dream for an Insomniac. She now has more than 20 films under her belt, mostly in a leading role and mostly as the droll, unlucky-in-love romantic – see He's Just Not That into You, Picture Perfect and The Object of My Affection for evidence. She may be a one-trick pony, but she's a veritable Derren Brown when it comes to romantic comedies.

These cynical, quite often facile films may lack depth, subtlety and, well, imagination, but Aniston never lets anybody down. In fact, now that Meg Ryan appears to have imploded, Aniston is probably – and this is a tad bold – the most gifted American comic actress of her generation. Her comic timing is immaculate and she could muster up playful sexual chemistry with a sideboard. And while her acting range isn't huge, she's never less than compelling.

For instance, in Ken Kwapis's wretched He's Just Not That into You – which focuses on various grating Baltimore couples hooking up and emoting – it's Aniston's endearing Beth that stands out above the likes of Jennifer Connelly, Scarlett Johansson and Drew Barrymore. We don't care two hoots for their dreary characters, but we do for Aniston's. How does she do it? And why can't she do it in superior films? Why haven't the likes of Martin Scorsese cast her in a gangster flick, Steven Spielberg in a fantasy spectacular or Ken Loach in a gritty drama? Why can't we see Aniston let rip? Play Shakespeare? Play a flesh-eating alien?

Well, there have been small attempts to widen her scope, and two low-budget films – Office Space and The Good Girl – are, by some distance, her finest films. Both films are set in small-town, "middle" America with an intense absence of glamour, culture or opportunity. In Mike Judge's exquisite satire on working life, Office Space, Aniston plays a bored waitress who is forced to don items of "flair" on her unsightly work attire. Her bone-dry delivery and resolutely stern demeanour are pitch perfect. It's a defiantly unglamorous role – although she's never looked prettier – and her character even loves kung-fu.

Miguel Arteta's downbeat The Good Girl could have been Aniston's moment, like Erin Brockovich was for Julia Roberts. Sort of. Once again she plays bored, this time as a supermarket checkout worker trapped in a sexless marriage to a dim-witted husband (John C Reilly) in mundane suburban hell in Texas. To escape the extreme monotony of her life, she falls for a JD Salinger-fixated teenage fantasist (Jake Gyllenhaal). And she's excellent; her down-turned mouth permanently drooped in gloom, her eyes deadened with tedium. It's the exact opposite of her animated, glamorous and kooky Rachel in Friends and her performance is all the better for it. However, the film made very little money and her chance to bag juicy acting roles seemed to have slipped away with the film's fortunes. She followed up The Good Girl with the lurid Jim Carrey vehicle Bruce Almighty, wasting her talents opposite the great gurning ham, and sleepwalked through the underwhelming Along Came Polly, which one critic described as "lame and unfunny and unoriginal".

Most recently, she once again tried dowdy and downbeat, in Stephen Belber's Management – a film so appalling it was shuffled out on to DVD with indecent haste. She plays a glum, uptight sales rep who pitches up at a motel in an American backwater and meets Steve Zahn's earnest suitor. It's the sort of territory in which Aniston usually excels, but here she just looks especially, well, sad. It looks as if she needs a great big bear hug, followed by a night in watching a comedy boxset. Ideally, early Friends, a place where people are "there for you", where men (David Schwimmer's nerd and Matt LeBlanc's hunk) fight over her and her hair is shiny and her smile is shinier.

"I don't get sent anything strange like underwear. I get sent cookies," Aniston once confessed. Maybe it's time for this persuasive actress to cut loose, get a bit kinky and stretch herself. Because, I, for one, still believe, that she's got it in her to act. It would be a pity, if only a slight one, if she's remembered solely as the gorgeous one on Friends and for "losing" Brad Pitt to Angelina Jolie. Come on Jen, some of us (me) are still on your side.