These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Fridge Logic: Orkans age in reverse. Which means as the years pass Mork will at some point physically resemble a teenager (and younger). This has some potentially very Squicky implications for his relationship with Mindy.
Also, the fate of Mork's girlfriend, who was swallowed by a black hole. "She didn't die. She just reappeared four years later and eight hundred times thinner." Shudder.
Harsher in Hindsight: In one of his appearances, Exidor goes on a long spiel extolling the virtues of O. J. Simpson.
In "Mork vs. the Necrotons", it off-handily mentioned by Captain Nirvana that the Necrotons could torture information out of Mork by rapping a rope round his neck, among other means. Robin Williams died by suicide from hanging.
At the end of "Mork in Wonderland: Part 2," Mork had only one wish upon reuniting with Mindy after her microworld counterpart, Mandy, died in his arms: for he himself to die before Mindy so he doesn't have to lose her twice. In a manner of speaking, Mork got his wish with Robin Williams dying in 2014 with Pam Dawber still around in good health.
Morgan Fairchild, who later carved a successful niche playing Rich Bitch characters in '80s Prime Time Soaps such as Falcon Crest, played Susan (Mindy's ex-classmate and romantic rival) in season 1.
Many actors who played minor characters had appearances on other shows in the '80s. A few examples: Jay Thomas later appeared as Eddie Lebeck on Cheers. Joe Regalbuto (a bad alien) went on to Murphy Brown. A very young Corey Feldman (Stand by Me, The Lost Boys) appears as one of Mork's day-care charges in a couple episodes. Dinah Manoff (Soap, Empty Nest) plays a woman who tries to extort Mork in the second season.
Seasonal Rot: Despite the show being a hit in its first season, changes were implemented in season 2 as a bid for younger viewers. Several characters - including Mindy's father and grandmother - were dropped, Mork and Mindy getting together received greater emphasis, and episodes had an altogether different tone. Coupled with a new timeslot, ratings fell, which led to attempts at getting back to basics.