If you ask me Roland's taste of humor is... amazing. It rocks.
Maybe we can't feel it so much in his character ( however I do) because:
- first of all his humor is very different from Eddie's
- secondly he doesn't like to waste his time with it,
and here we can see how different they are, I mean Eddie and Roland, Eddie has to say out loudly every funny things that comes to his mind, Roland gives them a free way just rarely.
But he did prove so many times that he has a good sense of humor.