Today’s TV fan spends a lot of time subconsciously managing a personal tolerance for despicableness. Bad behavior — from the violently criminal down to the basically ill-mannered — carries the day, but it has to be a certain flavor of bad for a show to really work, and tastes do differ.

Over in the world of literature, readers and reviewers argue these days about a character’s “likability” (particularly the likability of female characters in novels written by women) and whether or not likability is a reason to set a book down after 50 pages or so. “I just didn’t like her” is viewed as an intolerably facile criticism, often with good reason.

But over here on the couch, with remotes in hand and the broadband flowing like a river, we deal all the time with despicableness because our best and favorite TV series are nearly always built around flawed, often very unlikable people — mostly men — who make terrible choices and suffer from a provocative degree of narcissism. Despicableness is seen as a sure way to hook us in. I’d love to start watching a few shows about intensely likable people, but I can hardly think of any (“Call the Midwife,” maybe?) and life’s too short to watch Hallmark movies.

The likability factor once more brings me — unwillingly, this time — to the overanalyzed subject of Hannah Horvath, the still-24-year-old protagonist of the HBO series “Girls,” which returns for a third season Sunday night. “I just don’t like you,” a new character tells Hannah at her new job, midway through the new season. “I don’t like your face. Your mouth — I just want to rip it off your face.”

I wouldn’t go that far, but I do interpret the scene as yet another subliminal admission by Lena Dunham (“Girls’ ” creator and celebrated showrunner, who stars as Hannah) that she is essentially trolling for outraged responses from her detractors and fans alike. The point of watching is to exhaust oneself by tut-tutting Hannah for her perpetual entitlement and self-sabotaging journey toward adulthood. In 60 years of television, we’ve come to a point where we want this particular Lucy to literally choke on the chocolates coming off that conveyer belt — or, as it happens, the free snacks Hannah discovers in the corporate break room.

William H. Macy and Emmy Rossum in “Shameless.” (Cliff Lipson/Showtime)

At its best and worst, “Girls” enables an ongoing conversation about a very real generation gap. People older than 35 can use the show as a way to decide if people under 30 are as inept and self-absorbed as they’re depicted (mostly anecdotally) in media reports and socio-psycho-economic-demographic studies. Others of us can watch “Girls” as an opportunity to be patronizingly amused by the growing pains of the younger generation.

Rather than rise up against the very narrow millennial stereotype depicted in “Girls,” viewers in their 20s are drawn to it, and drawn to affirming the show in quasi-critical essays and recaps posted online. And I do understand why: “Girls” is about a despicably self-centered young woman and her mostly despicable social circle. It is both an indictment and an exaltation of an entire subspecies of young adult.

In this season, all of “Girls’ ” problems and quarter-life crises remain firmly intact. The once-ascendant Marnie (Allison Williams) is now just heartsick and aimlessly adrift in her dreams of singing success (and singing humiliation, via an Edie Brickell cover on YouTube); Shoshanna (Zosia Mamet) regrets dumping Ray (Alex Karpovsky); the cartoonishly irritating Jessa (Jemima Kirke) is tormenting her fellow addicts at a bucolic rehab center upstate.

The grittiness of “Girls” crossed a line last season into abject disgust. The show became less about satire and more of an obsessive downer. It’s a lot less fun now; when watching these new episodes, I found it impossible to complete any sentence along the lines of “I hope [blank] happens to [blank],” not counting my hope that poor Adam (Hannah’s increasingly complex boyfriend, played by Adam Driver, who now provides the show’s only gravitational pull) will come to his senses and flee. I don’t hope anything happens to Hannah or Marnie or especially Jessa, because “Girls” forgets to offer any payoff or engagement as a TV show; Shoshanna is the only one of them I’d really keep watching a show about, if it came with a laugh track. One intriguing arc involves Adam’s sister, Caroline, played by Gaby Hoffman, who turns out be exactly the sort of disruptive trouble “Girls” needs; she’s someone who might have real mental issues, instead of just dabbling in them.

Early in the season, Hannah confronts mortality; an acquaintance has died, but all it triggers, emotionally, is a worry about how this death might affect Hannah professionally. Adam, now saddled with representing “Girls’ ” mere hint of a moral center, is once more baffled at her selfishness and her inability to process feelings.

“Why are we fighting about this?!” Hannah asks, looking up from her computer screen, where she has been reading anonymous comments about the death on Gawker.

“Why aren’t you mourning quietly?” Adam wants to know.

1 of 8 Full Screen Autoplay Close Skip Ad × ‘Girls’ Season 3 premiere View Photos Cast members and others celebrate the third season of HBO’s series about four friends living in New York. Caption Lena Dunham, Allison Williams, Judd Apatow and others celebrate the third season of HBO’s series about four friends living in New York. From left, "Girls" stars Jemima Kirke, Lena Dunham, Allison Williams and Zosia Mamet celebrate the show's third season at Jazz at Lincoln Center. The premiere airs Jan. 12 on HBO. Charles Sykes/Invision via AP Buy Photo Wait 1 second to continue.

Because she doesn’t have it in her. We are talking too much about a show that is only about the hollowness of empty, despicable people. Ignoring “Girls” doesn’t mean you’re old or missing a joke or even that you’re anti-feminist. To the extent that I can confer it, I’m giving those of us who have had enough “Girls” permission to get on with our lives, for whatever reasons, including unlikability.

‘Shameless’

What I said above, about despicableness being a personal taste? Here’s proof: Over on Showtime, also on Sunday night, is a much more welcome return of horrible people: “Shameless,” John Wells’s Americanized version of the British drama, returns for a fourth season.

With surprisingly little acclaim and virtually no need for “Girls”-style analytical unpacking, “Shameless” chugs (and chugs) along. Relentless prurience is certainly a hurdle here (“Shameless” is filled with sex, as well as puking, lying, stealing — you name it) but the despicableness is of a much more contextual variety, as we catch up with the downtrodden Gallagher clan of Chicago, held together by eldest daughter Fiona (the splendidly on-point Emmy Rossum).

Fiona is a contemporary of Hannah Horvath in age only, saddled with raising her siblings after her no-good father Frank (William H. Macy) went on a never-ending bender years ago; Fiona is now on the precipice of solvency, as a cubicle job gives her just a hint of life with an honest paycheck, a health plan and a 401(k).

It can’t last, not when one is a Gallagher, because a Gallagher cannot have nice things. The show is held together by a sort of “Gee, Officer Krupke” sense of morality: They’re depraved onna-count’a they’re deprived. (Whereas in “Girls,” they’re depraved onna-count’a they went to Oberlin?)

Second-oldest Lip (Jeremy Allen White) is attending college across town on scholarship, chafing against the privilege all around him in the dorms and classrooms, and also discovering that he’s not the academic genius he had believed himself to be. Younger sister Debbie (Emma Kenney) depressingly approaches the gritty, brutal and ever-present sexuality all around her, while little brother Carl (Ethan Cutkosky) is self-discovering with wild abandon in his upper-bunk bed. Neighbors provide a large part of “Shameless’s” version of comic relief: Steve Howey and Shanola Hampton are consistently watchable as the hypersexual couple-next-door; Joan Cusack’s immeasurable talents have been put to good use as the Gallagher family’s quirky agoraphobic neighbor.

And although the show ostensibly centers around him, Macy’s Frank seems the least relevant or interesting this time around — perhaps gearing up for a timely exit, as Frank crashes back into the Gallagher household with a non-functioning liver, reduced to imbibing alcohol via eyedrops and enemas.

Like I said: Gross, disgusting, despicable. And yet it’s a show I find myself routinely encouraging restless viewers to go back and watch from Season 1. “Shameless’s” balance between humor and despicableness is a lesson in narrative wallowing that “Girls” ought to study.

Girls

(30 minutes) returns Sunday

at 10 p.m. on HBO.

Shameless

(one hour) returns Sunday at 9 p.m. on Showtime.