This week, “This Is Us” returned for a installment that was curiously low on Kleenex requirements, “Modern Family” delivered another endearing Valentine’s Day special, and “Young Sheldon” offered brief moments of promise in an otherwise stale episode.

‘This Is Us’

“This Is Us” pulled off something truly shocking this week: It didn’t turn viewers into a sobbing puddle of tears. After the Big Mac-sized wallop that was the past eight episodes, we were treated to a happier chapter in the lives of the Pearsons.

The defining feature of “Vegas, Baby” is the rare opportunity that it provides for most of its collective ensemble to come together. Unlike, say, “Modern Family,” “This Is Us” largely chooses to isolate the members of its central cast into their own separate cocoons. That creative choice is why big family events like bachelor parties, weddings or Thanksgivings seem so special: They provide an avenue for the talented cast to play off each other.

Indeed, it is refreshing to watch Kate (Chrissy Metz) get her own hang-out time with Randall (Sterling K. Brown) and to see Toby (Chris Sullivan) have a conversation with someone other than Kate.

While teenage Kate’s (Hannah Zeile) surprising closeness with teenage Randall (Niles Fitch) seems to come out of nowhere, it nevertheless furnishes a compelling layer to her dynamic with him in the present. The relationship between Kate and Randall has been the most undercooked one in the permutations of the Big Three seen so far, and it is necessary for “This Is Us” to dig deeper into this bond moving forward.

Furthermore, the writing choice to make Kate intimidated by Beth (Susan Kelechi Watson) is fitting with what we know of Kate’s character. If Kate and Randall were close in the past and haven’t had the best relationship in the present, then it would make sense for Kate to place the blame for that on Beth, just as she used to blame her mom for her insecurities about her weight.

True to the nature of “This Is Us,” the initial ice-cold vibes between Beth and Kate are mined for every ounce of drama possible before they inevitably patch up in a characteristically earnest, syrupy scene. Their reconciliation also works as an effective demonstration of Kate’s ongoing efforts to battle her lingering self-doubt.

Toby’s desire to bond with Kevin (Justin Hartley) and Randall through his bachelor party provides another low-stakes, easy-to-watch storyline of the variety that “This Is Us” does so well.

We are also treated to an entire storyline in the past that shows Jack (Milo Ventimiglia) and Rebecca (Mandy Moore) being adorable and in love. Watching them fret about something as small as an anniversary present is a much-needed respite from all the doom and gloom the pair has faced together.

Essentially, save for a stretched-out argument between Randall and Beth in the present — which also gets a quick, speedy resolution — “Vegas, Baby” is an episode that’s eminently watchable because of how breezy and enjoyable it is. There is no death looming over the horizon, nor is there an emotional wringer foreshadowed. It just follows all of these different characters getting together and having some fun. And fun is exactly what “This Is Us” needed.

‘Modern Family’

The Valentine’s Day-themed episodes of “Modern Family” always turn out to be the standouts of their respective seasons, and “Written in the Stars” is no exception.

We get Joe (Jeremy Maguire) trying to pull off the classic, James Bond-like act, Mitch (Jesse Tyler Ferguson) and Cam (Eric Stonestreet) being their best, gossipy selves and Haley (Sarah Hyland) finally getting to show off her trademark blend of insecurity and ditziness. Oh, and there are so many speeches about love — including a particularly warm one by Mitchell  — that it’s impossible not to melt.

As with previous Valentine’s Day installments, this episode acts as a love letter to the show’s central relationships. Jay (Ed O’Neill), who has been operating under the umbrella of “curmudgeonly old man” for far too long this season, especially benefits from the spotlight on his relationship with Gloria (Sofía Vergara).

Realizing that he needs to make more of an effort in his marriage is a genuinely thoughtful character development. Hopefully, “Modern Family” won’t treat Jay’s personal growth as a one-and-done and will continue to flesh out his increased commitment to Gloria in episodes to come.

Cam and Mitch prove to be the episode’s scene-stealers. Let’s face it, after Luke’s (Nolan Gould) transformation into “dumb, heartless playboy,” somebody needed to take him down a peg or two. Cam and Mitch were the best people for the job. Their Luke-centric roasts are genuinely hilarious, as are their later attempts to redeem him in the eyes of the girl he liked.

Mitch’s speech about the care and affection he feels for Cam is also a welcome breath of fresh air for “Modern Family,” which has taken a sadistic pride in pitting the two against each other for the majority of this season.

Haley’s date is another unexpectedly fascinating storyline, and not just because of how it pits her against Alex (Ariel Winter) at its end. “Modern Family” sometimes forgets that Haley is an actual person with doubts and insecurities of her own.

Here, we witness some of those insecurities and learn that she is at the point in her life where she is reflecting on whether her accomplishments so far have been enough. Haley’s entire arc does more to distinguish her character than any storyline has in quite a while.

“Written in the Stars,” then, finds “Modern Family” in top form after its nearly two-month break. It is sharply written and well-balanced, and it justifies why these opposing personalities are together in the first place.

‘Young Sheldon’

One of the few saving graces of this mediocre half-hour is an actual blink-and-you-miss-it moment of development in the relationship between George (Lance Barber) and Mary (Zoe Perry). In classic sitcoms like “Everybody Loves Raymond,” the husband actively tries to stop his wife from going to work.

“Young Sheldon,” however, wisely chooses to eschew that tired bit of manipulation. George is happy to see his wife so passionate about her new job. Like any supportive partner, he encourages her to stick to her new responsibilities after the two fail to recruit a suitable babysitter for Sheldon (Iain Armitage) and Missy (Raegan Revord).

While “Young Sheldon” has recently succumbed to many of the conventionalities of the family-focused sitcom, it’s still relieving to see that it has not sacrificed all of the sincerity that was the hallmark of its first few episodes.

Another notable highlight is the “Operation” sequence with Missy and Sheldon. Based on how she initially reacts to Sheldon’s splinter, it is easy to assume that Missy does not really empathize with some of Sheldon’s idiosyncrasies — she doesn’t understand that he needs the splinter out immediately. But when Missy rushes to get the “Operation” box because she remembers that there is a tweezer inside it, “Young Sheldon” is able to show that the two children do care about each other.

These sprinkled-in moments of depth are proof enough of the potential that “Young Sheldon” has. It doesn’t need to travel the well-worn route of mediocrity that most sitcoms actively pursue. With its endearing cast and promising relationships, the only thing “Young Sheldon” has to do is create compelling enough plots for their chemistry to shine.