"You're like me," Cole can't help but respond, looking directly at Papyrus. Just a skeleton instead of a spirit. Cole doesn't really think of happiness in terms of himself. Oh, there are things he likes, but the best feeling of all is easing someone else's hurt. It's nice to see that he can find a kindred soul even among those who aren't spirits. It's not really shown in his face but there's a little twinge of happiness in Cole's voice.

"Except for the fact that I have skin and you don't."

Well, yes. And a whole lot of other factors but apparently this is the point that Cole's still focusing on.