The adorable soot ball creatures are working so hard, one of them collapses pitifully under the weight of the coal it is carrying... Chihiro helps it out, taking the coal off it and putting it in the furnace for the soot creature. The other soot creatures' response? They all pretend to be crushed by their coal.
No Face's spewing, roaring rampage dwindling down to stumbling after Chihiro and hacking up some goo, after which he politely excuses himself.
Yubaba's frantic search for Boh.
YMMV, I found that rather heartbreaking.
Chihiro's tentative climb down the very high, very long staircase to the boiler room—then when one of the steps near the top breaks, her running full-speed down the rest of it, screaming at the top of her lungs, and finally crashing into the wall at the bottom.
It happens again later when No Face is chasing her, and then No Face crashes into the wall, too!
When Yubaba tells Haku that she's going to give Chihiro one final test, a whole crowd gathered on top of the bathhouse boos Yubaba and she yells, "SHUT UP!" and they quickly retreat.
Mouse!Boh and a sootball re-enacting Chihiro squashing the slug and Kamaji ridding her of the bad luck. You can't help but admit that it's funny and cute at the same time.
Most of the scene where "No Face" was eating everyone in the bath house was Nightmare Fuel... but the scene where he yells "Wipe that smile off your face! You're STILL SMILING!" before eating one guy was too funny to be scary.
During the "stink spirit's" arrival, Sen quite understandably is covering her nose, until Yubaba snaps (while looking like she's about to faint herself) "Put your hands down! You insult our guest!"
The smell is so bad it makes Sen's hair stand up.
It gets even funnier when the spirit holds out some slime-covered money to pay for his stay at the bathhouse, and Yubaba dumps the task of taking it on Chihiro. Her reaction is priceless.
When Chihiro returns to the bathhouse, she keeps calling Yubaba "Granny" - forgetting she's not Zenibanote Zeniba asked Chihiro to call her that and Yubaba's reaction is priceless.