Simply put, being a slacker is great; it makes him happy.
For someone like Motan, who has zero chance of turning into a true slacker in the real world and has felt as if he's constantly being pushed to his limits even in the game, being able to take a moment to chill and laze around is truly a pleasure. Of course, even now Motan isn't actually idle; he just dislikes bearing pressure and expectations.
Honestly, even Yu Chen's expectations of him are a bittersweet affair. The happiness part doesn't need explaining, but the pain? That comes naturally from his utter lack of ambition, to the point where he possesses no trace of a drive for improvement.
Unfortunately, life has never been something that bends to personal will. Even in this Realm of Innocence, where he theoretically has some dominion over his own fate, the same applies.
