Xon realizes that the reason that Spock performed so well in his tasks on board the Enterprise was that he was half Human and therefore could understand emotional Human nature. In order to perform as well as Spock, he knows he is going to have to eliminate his Vulcan revulsion at emotional displays. He is, in fact, going to have to reach down within himself and find the emotions that his society has repressed for thousands of years so that he will have some basis for fully understanding his Human associates.
What this means is: whereas Spock was engaged in a constant battle with himself to repress his emotions in order to be more Vulcan-like, Xon will be engaged in a constant struggle within himself to release his buried emotions to be more Human-like for the sake of doing a good job, his primary considerations. This will be at least as difficult for him as it was for Spock to maintain his stoic pose. Also, we'll get humor out of Xon trying to simulate laughter, anger, fear, and other Human feelings.