It ought to be simple: A new sitcom can succeed if it features actors and/or characters you like and if it’s funny.

But what about a sitcom that features some actors and/or characters you like and is only occasionally funny?

Then you have problems, and that’s a good way to describe CBS’ “The Millers” and NBC’s “Sean Saves the World,” which premiered recently along with a better new show, “Welcome to the Family,” also on NBC.

Margo Martindale is the best reason to watch “The Millers,” just as she’s the best reason to watch almost anything she’s in.

The brilliantly shape-shifting character actor goes for broad comedy playing a nagging wife to dopey Beau Bridges (“Masters of Sex”) and meddling mom to her newly divorced son, played by Will Arnett.

As for the rest of the family, not so much. After the debacle that “Up All Night” became and now with “The Millers,” Arnett plays Nathan Miller, who’s been afraid to tell his parents that he’s been divorced for three months.

When he finally spills the beans, his dad, Tom, decides that if Nathan can get divorced, so can he. While Carol Miller moves into Nathan’s apartment, Tom goes to live with Debbie (Jayma Mays, “Glee”), Nathan’s sister.

The show has its moments, but almost all of them belong to Martindale. Bridges plays the dear-old-dumb-dad bit to the hilt.

This is somewhat surprising fare from Greg Garcia, who created “My Name Is Earl” and “Raising Hope.” The surprising part is that he doesn’t even try to nudge the envelope as he did with both of those shows.

Sean Hayes returns to series TV after producing “Grimm” and “Hot in Cleveland.”

Hayes essentially plays the same character he played in “Will & Grace,” except for two factors: He’s out now, and his character, conveniently named Sean, is the gay single father of a teenage daughter named Ellie (Sami Isler, “Home Run”).

The good thing about “Sean Saves the World” is that it’s an ensemble show. The bad thing about that for the show is that we’re often happier to see the supporting characters onscreen than we are Sean, whose constant state of frenzy gets tiresome.

But consider the supporting players: First, foremost and then some, you have Linda Lavin (“Alice”) playing Lorna, Sean’s domineering mother.

Then there’s Thomas Lennon (“Reno 911”), whose singular brand of comic insanity makes him a gift from heaven for “Sean Saves the World.”

Megan Hilty (“Smash”) proves an able comedienne as Sean’s best friend, Liz, who wants to be a big sister to Ellie.

Some of the early episodes’ best scenes pit Lavin and Hilty against each other, each marking her respective territory for dominance of Sean and Ellie.

Hayes is a gifted comic actor who hasn’t really shown much range heretofore. Yes, there is room for over-the-top, but could we have that in smaller doses, please?

“Welcome to the Family” may have the most potential of the new Thursday comedies, for the simple reason that it depends largely on careful character development as the grounding for its humor.

That said, it’s up against “The Millers” and ABC’s “Scandal” on Thursday night, which doesn’t bode well.

This is “Romeo and Juliet.”

Two new high school graduates, Molly Yoder (Ella Rae Peck, “The Call”) and Junior Hernandez (Joey Haro, “Awkward”) have their futures in front of them, and those futures will now include a child, much to the shocked disappointment of their respective parents.

Junior hasn’t told his parents about the baby, but Molly has told her physician father, Dan (Mike O’Malley, “Glee) and her mom Caroline (Mary McCormack, “In Plain Sight”).

They are still trying to process the information when the Hernandez family turns up for dinner. It’s one thing to find out that Junior is going to be a dad, even before they’ve sat down to dinner, but quite another thing when Miguel Hernandez (Ricardo Chavira, “Desperate Housewives”) recognizes Dan as the lout who had shown up at his family-owned gym and promptly picked a fight.

Dan denies that Junior’s ethnicity is the reason he doesn’t want his daughter marrying him: It’s not Latinos he dislikes, he says, it’s Miguel.

We’re going to have these discussions with greater frequency, at least I hope so, because that will mean Latinos are being featured more often in leading roles on TV, something that’s way overdue on television.

Dan and Mike do not get along, but it’s entirely personal, and it’s the kind of not getting along that suggests the inevitability of finding common ground as their kids try to negotiate parenthood.