"I don't suppose you'd accept the excuse of 'I didn't want to be late'."

Because they both know that he didn't really care about whether he was going to be late to the multiverse Halloween party. It was like pulling teeth just to get him to leave the Enterprise, though he's secretly happy for the change of scenery.

"You're acting like I'm being glib, but I am so tremendously happy I got to come and see you ..." He gestures with a vertical wave of his hand. "... in that."