As bright as diner condiments and as sweet, tangy, and essential, Bob’s Burgers concluded its sixth season -- and its 100th episode -- last night. The animated series, about a family of five working and hanging out at a modest, barely-scraping-by restaurant, continued its proud tradition of handing patriarch Bob Belcher (voiced by H. Jon Benjamin) minor trophies that it first dings, then snaps in two, then runs over with a bus. Hours before he’s to be interviewed as an undiscovered gem for a big, shiny magazine in the finale, Bob found himself glued to a toilet, the victim of a prank by his 9-year-old daughter Louise (Kristen Schaal). For Bob, there’s no such thing as a free lunch -- and, happily, it looks like it’ll stay that way for a while.

Renewed for the next two seasons, Bob’s Burgers joins The Simpsons and Family Guy as Fox’s Sunday-night institutions. But unlike those two older shows, it’s still in the prime of its life, boasting a superlative voice cast, expertly crafted characters, and endless wit, heart, and insight. Originally pitched with cannibalism as the hook, it has instead become one of the most invitingly homey series on television, though it always knows when to cut the sugar with dry zest. And in our time of highly fragmented viewership, it’s also one of the few shows seemingly made for everyone.

But what may be most crucial to the long-running success of Bob’s Burgers are its subtle updates to the family sitcom. The genre has long brought affable progress into viewers’ homes, starting with Norman Lear classics like All in the Family, The Jeffersons, and One Day at a Time. In the ‘80s and ‘90s, Roseanne and The Cosby Show proved that all sorts of families belonged onscreen -- a push forward in discourse and demographics that continues today with Black-ish, Fresh Off the Boat, The Carmichael Show, The Middle, and, more loosely, with Transparent and Jane the Virgin. Happy families are all alike, as the saying goes -- the reason, perhaps, why change is easier to introduce when it feels pretty similar to what came before it.

Bob’s Burgers nails that balance between familiar and fresh while reintroducing that most underrated of sitcom virtues: fairness. In contrast to “The Homer Show” that The Simpsons has become and the smug derision Family Guy flings at everything it can think of, Bob’s Burgers is on the side of all five Belchers, approaching them with warmth and curiosity.

This past season, for example, nearly all of the core characters enjoyed at least one great episode that pushed him or her in new directions. Bob broadened his horizons -- and considered the physical effects of stress -- in “Sexy Dance Healing,” a welcome sequel to the capoeira-centric “Sexy Dance Fighting” episode of the first season. And in “The Land Ship,” the show’s best character, 13-year-old good-girl Tina (Dan Mintz), flirted with moral compromise by getting into a secret relationship with a none-too-smooth graffitist (Nathan Fielder) in her class. “I guess bad boys are bad kissers,” she reasons with disappointment.

Bob’s Burgers fares least well when it veers too far from its rust-belt, working-class milieu, which grounds the show and makes space for its musical or surreal flights of fancy. This season, its reality teetered a bit more, as usually happens when the Belchers encounter more than a morsel of good luck. That was the case with “Bye Bye Boo Boo,” when Louise meets her blond-banged boy-band crush Boo Boo (Max Greenfield), whom she hates herself for adoring so much. But even that episode was redeemed when big sis Tina, the show’s casually revolutionary poster child for nascent female sexuality, gave Louise a great talk about not letting her prejudices about what’s cool dictate her passions: “It’s OK for you to be excited …. Just because you think something is embarrassing doesn't mean you have to be embarrassed by it.” Unfortunately, mom Linda (John Roberts) and middle child Gene (Eugene Mirman), the kind of playfully genderqueer boy who sincerely believes himself to be born to be a mother, did draw shorter straws this year.

In a TV landscape rich with, well, affluence, it’s refreshing to see an innocent and relatable blue-collar family who defy their struggles with their collective creativity: Bob’s food, Linda’s manic whims, Tina’s “erotic friend fiction,” Gene’s music, and Louise’s megalomania. Theirs is the hope and imagination of everyday life, and it's all the more poignant for it. As long as Bob’s Burgers can maintain the small intimacy of its stories, it’ll continue to give “family-friendly entertainment” back its good name.