Sukuna isn't a good person - he's the epitome of a cruel man. He's hurt people, hurt himself; all for power. To be honest, he barely has time; Sukuna is a feudal lord, the pinnacle of power in the Heian Era - which is the most robust Era of Jujutsu sorcery. But he does have some affection for your company - you're his personal samurai, an exceptional one. 'Bring me heads' kind of thing. He loves seeing you so devoted. Because he knows you hate him.