All the way back in the pilot, Princess Carolyn recalled an incident where BoJack implied that he wasn't ready to have kids with her: Princess Carolyn commented on how cute a baby was, and BoJack responded by freaking out, knocking the baby over, and running away.
And now, years later, we see the mother and her child again - behind Todd and Courtney in the Italian restaurant! And, of course, the mother's wearing the exact same dress (and her child is wearing a similarly-colored outfit) to really drive home the point.
To be fair, this isn't the first time we've seen them since the pilot - they briefly showed up in season 2, as BoJack stole the child's stroller:
Still, it's nice to see the mother and her child doing well - and this is their first appearance where BoJack didn't accost the stroller!
Way, way back in season 1, Todd was briefly interred in prison (after mistakenly showing off BoJack's house as David Boreanaz's, and the ensuing schemes) and was solicited for membership by both the Latin Kings and the Aryan Brotherhood - and Todd, afraid of offending either group, attempted to placate them both by indicating to each he would be joining their group...and by getting tattoos on opposing arms, labelled "LATIN KINGS" and "SKIN HEADS."
These tattoos were still visible on Todd's body as of season 3:
But sometime between season 3 and season 4, Todd decided it was time to do something about his gang tattoos - and since removal was apparently too expensive of an option, Todd decided to find some more affordable routes - crossing out the "TIN" in "LATIN KINGS" so it would read "LA KINGS" (after Los Angeles' hockey team) and adding "NY" and "jug" to "SKIN HEADS" so it would read "SKINNY jugHEADS" (which is sorta a reference to Archie Comics' character Jughead, who - like Todd - is famously asexual):
In short, HOLY CRAP THIS SHOW PACKS THE JOKES IN.
In the gut-wrenchingly depressing (even for BoJack Horseman) episode "Time's Arrow," we get further glimpses into the past of Beatrice Horseman (nee Sugarman), as her dementia-addled mind has her lost in memory. But the memories are a bit faded and unclear - notably the faces of many individuals in the background being obscured, scratched out, or simply missing.
But what would BoJack Horseman be if not a show willing to toy around and make jokes with its own conventions? While Beatrice is on a date, there's a couple in the background having a picnic (the fact that one of them is an ant is already a pretty solid joke on its own) - but if you watch the bear, he's trying to eat a baguette....except that he realizes he doesn't have a mouth, so just tries to jam the bread into his featureless face and gets confused when it doesn't work.
In preparation for his gubernatorial ski race, Mr. Peanutbutter signs up for ski school - which turns out to be an actual full-fledged college, even with a requisite inspiring teacher, Professor Thistlethorpe. The gag of the sequence is how quickly Mr. Peanutbutter moves through his lessons and the tropes of films about inspiring teachers, mirrored by Professor Thistlethorpe's own quickened lifespan - as he goes from caterpillar...
...to the cocoon stage (right before Mr. Peanutbutter's graduation)...
...to a beautiful, winged butterfly (as Mr. Peanutbutter gives his impassioned governership speech)...
...to a dying, old man, whose wings have fallen off (outside the VIM Agency in "Stupid Piece of Shit").
You lived a full life, professor....and all in the first six episodes!