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.
YMMV: It
Complete Monster: There's IT obviously, but also present are Tom Rogan and Patrick Hocksetter.
Some say Henry and Butch Bowers qualify as well.
Compressed Adaptation: The movie. It's pretty hard to stuff over a thousand pages of story into a movie. Most agree that Tim Curry was memorable as Pennywise, however.
Freud Was Right: It is implied that Beverly's father was attracted to her.
Fridge Logic: One could argue that the whole concept of IT is sort of an Evil Counterpart to the Christian Trinity. There's the "Father" (IT's Giant Spider form), the "Son" (Pennywise, who is IT in "human" form), and the Unholy Spirit (the deadlights, IT's spiritual form).
Foe Yay: It's movie only, but the scene where Adult Ben thinks he's kissing Beverly when it turns out to be It in drag, who then shouts "Kiss me, fat boy!"
Ham and Cheese: While Tim Curry's performance as Pennywise, in the movie, is viewed as pretty scary by many, he also gives it a healthy dose of this, and it is ever so glorious.
Nightmare Retardant: Whenever he goes over-the-top and silly. "Excuse me sir, do you have Prince Albert in a can? You do? Well ya better let the poor guy out! WAHA! WAHA! WAHA! WAHA!"
Hilarious in Hindsight: Pennywise is played by Tim Curry. The monster is revealed, at the end of the book to be female. Tim Curry is therefore, once again, playing a transvestite.
Moral Event Horizon: Henry almost crosses this when he begins to carve his name into Ben's stomach with a switchblade, and then becomes a Complete Monster when he decides to murder the Losers one by one as payback for the rock fight. But just before that he crossed it when he murdered his father in his sleep with a razor IT gave him.
Patrick crosses it when he smothers his baby brother.
Special Effects Failure: IT's spider-form at the end of the movie. The true metaphysical nature of IT is only vaguely referenced. It looks very cheap and results in quite an Anti-Climax. To be fair, the cosmic elements of the novel would be tough to replicate on the screen. The Stop-Motion effects too.
The Woobie: Every one of the Losers qualifies, with the possible exception of Richie.