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.
(the shooting star hits a passing airplane and both explode)
Catherine: *epic jaw drop*
Heartwarming Moments: Shockingly, this also exists. In The Second Guest and the PS2 game, it's the scene when the Guest has a chance to escape the hotel...and they turn around to go back, deciding they don't want to leave without taking Neko Zombie with them. He refuses the offer, saying he doesn't deserve to leave, and shows the wounds he has from his shackles. The Guest takes a handkerchief and wraps the wound.
Then in The Bloody Karte, there's a brief period in episode eleven where Catherine decides it'd just be better if she left the hospital, and prepares to leave with her bags packed. Gregory actually tells her not to leave, saying that she has patients that still count on her, and she's needed here. It's the boost Catherine needs to immediately cheer up and decide she'll stay in the hospital.
The second-to-last episode of Last Train. "I'm ready to see what I have to. My conscience is no longer binding me... for I myself am the conscience."
Moral Event Horizon: Gregory for torturing and rendering Neko Zombie as he is now, while keeping him imprisoned in the hellish hotel. And Gregory Mama, for capturing and consuming lost souls all for revitalizing her "beautiful" self.
TV Fish is generally the most benign resident of Gregory House in that it doesn't outright try to kill or harm anyone. But it also projects memories of those it comes in contact with, particularly painful memories...
One-Scene Wonder: A good handful of the characters in the series only pop up in one short for the entire run.
Catherine thinks this of Haniwa in The Bloody Karte.
The Second Guest is a bit of this as well. She had just left from a wedding when she found Gregory House, a wedding between her best friend and her ex-boyfriend. Her ex had broken up with her after she said she wanted to work on her career first before she got married, and apparently she never got over it. You can see her slowly beginning to break down because of this as the series goes on.