My favorite arc is John and Karkat becoming friends but backwards. Genuinely brings a tear to my eye seeing them go from like mortal (lame) enemies to having John go "Oh my god! Karkat Buddy it's you!! Hi!!" and genuinely being excited when he finally gets to THE first time Karkat talks to him. Karkat is confused because the first time he ever spoke to John, moments before he saw the guy's whole life story and decided he hated him more than anything. But then by the end they're like best buds

It's heartwarming okay, I too liked seeing Karkat learn that strange human emotion called Friendship. I even liked that when Karkat said that, he was knowingly repeating John's words to him. The person who taught him that friendship WAS an emotion was John T_T