Another big reason why the ray may be my favorite card is because of something extraordinary that happened during the final of the Harmonies Lotus tournament (where we met in quarter finals, I believe).
The tournament was played with 4 players, on side B, without spirits. During the final, I was having a decent game, not great, probably not enough to win. I went for the bat on my first turn, hoping to get the ray at some point, but it didn't come, so I had to delay things and opt for the frog instead. But I kept hoping for the ray, and on my penultimate turn, figuring that it was my only chance of winning, I decided to set up my board for a ray that wasn't there.
When they played their last move, the player before me decided to pick up a card, probably to prevent the player after me from getting it. But in doing so, they offered me the victory: the ray was revealed on my last turn, giving me a free 16 points along with the perfect set of tiles to finish my board beautifully. I ended up winning that final by a good margin, thanks to that last minute ray apparition.
So, in a way, the ray is an important card for both of us, for different reasons.