Wait so why did didnt Karkat go back towards the beginning to troll John ? Was it just because he arbitrarily decided to at one point and stuck to it all the way through?

CG: OK, LOOK.
CG: LET’S JUST AGREE TO NEVER BRING IT UP AGAIN.
CG: THE STUFF I WAS BABBLING ABOUT EARLIER.
EB: yeah, well we never really talked about it in the past, so i guess we do agree to that.
CG: BUT IF I TALK TO YOU AGAIN
CG: IN YOUR FUTURE, LIMITED THOUGH IT IS
CG: YOU’LL REMEMBER MY EMBARRASSING SHIT
CG: SO I GUESS
CG: I’LL HAVE TO TROLL YOU BACKWARDS?
EB: told you bro!!!!!!!
EB: hahahaha.

Self-fulfilling idiocy, really.