Any of Karkat's attempts to crash the trial, and how Terezi responds to them with an instant ban. But the best part is when three different future versions of him appear and tell off Past Karkat, and then there's how they exit the memo:
FCG: *THE KNIGHT OF BLOOD AND HIS TWO FUTURE SELVES FUSE INTO SOME KIND OF BIOMECHANICAL SUPER SOLDIER AND FLY OFF INTO THE NIGHT SKY ON THEIR NEWLY-ACQUIRED ROCKET BOOTS, LEAVING THE OCCUPANTS OF THE COURTBLOCK COUGHING UP EXHAUST*
FCG2: *THEY JUST LEAVE THE FLAMINGLY-WINGED HOOFBEAST THERE JUST FOR THE HELL OF IT*
FCG3: *MIGHT WANT TO GET SOME ASBESTOS GLOVES TO CLEAN UP THAT THING'S LEAVINGS, ASSHOLES, HAHAHAHAHAHA*
FCG: *FUCK YES, FUTURE HIGH FIVES ALL AROUND*
After Gamzee sobers up, he starts baking pies — actual pies, not slime pies. After he goes god tier, he gets so good at baking pies that he (accidentally!) discovers an entire line of quests based around starting a baked goods corporation.
Also, at one point he gives a pie to Karkat, who then proceeds to have a huge overblown flip out because Gamzee put Faygo in the pie.
Eridan, tired of angels invading his hive, lets them kill him and he ascends to God tier. What makes it funny is his exchange with Terezi afterward.
FGC: OH MY GOD
FGC: THOSE 4R3 TH3 DORK13ST P4NTS 1V3 3V3R S33N
FCA: oh wwoww THATS nice
FCA: i just got ritually sacrificed an the first thing you do wwhen you see me alivve is insult my fuckin wwardrobe
FCA: im touched really
Eridan and Equius discuss how Equius would be a lousy kismesis for Gamzee until he learns to stop putting so much stock in the hemospectrum, because he's no good as a rival if he obeys every order Gamzee gives. Equius tells Gamzee this. Gamzee proceeds to order him to tell Eridan he loves him and wants to "fill all the buckets" with him. And he does.
Early on, some of the trolls are talking, soon after Tavros and Vriska become moirails.
PAG: Sorry, I'm just kind of used to moirail stuff 8eing more intim8.
PAG: Like when your moirail m8kes a 8unch of skimpy outfits and t8kes pictures of you trying them on.
PAG: Or when you t8ke a 8ath and your moirail scru8s down your whole 8ody for you.
CAC: :33 < er
PAG: ........Neither of those are actual moirail things, are they?