In Raymond Carver's minimalistic story, "Cathedral," the irony, or contrast between what is expected and what really hapens, occurs in the latter part of the narrative.  For, it is the sensitive wife of the narrator who has made friends with Robert and invited the man to her home in hopes of engaging in conversation and discussions of her poetry with him since her husband does not share such interests; however, it is the cynical husband/narrator, displeased with her invitation to a blind man to stay at their house, who truly interacts with Robert and has a delightfully creative shared experience with him as together they draw a cathedral, an experience which taps into the very spirit and imagination,   

My eyes were still closed. I was in my house. I knew that. But I didn’t feel like I was inside anything.

The contrast of these remarks with others of the narrator's is marked as earlier the narrator ridiculed spirituality in the saying of grace before the meal,

“Now let us pray,” I said, and the blind man lowered his head. My wife looked at me, her mouth agape. “Pray the phone won’t ring and the food doesn’t get cold,” I said.

The change effected in the narator is so great and so genuine that even he is suprised, "It's really something."