Probably a bit of gap moe - simply catching them in a different light. I think everyone enjoys it when characters act different than what they're used to because of something you did. Making the stoic turn not so stoic is always fun!
If you're into the glasses trope, Caine wears them every now and then as well, not as often though since he thinks he looks lame in them.
And ah, if you own a Mac, I'm hoping to release a Mac version sometime. I need a friend's help with this though, and currently she seems busy with other projects, so I don't have an ETA.