The awkward moment when I realized that the mind reader didn't smile in the entire first book.
(I mean... it's the mind reader! Without his smile, he has nothing but his alice! And even that's not the same without his chronic smile!! Until chapter 6 [when he started to smile a little] he was a nobody!!!!)
By the way: Didn't they tell us that Sumire was the one who made him laugh all the time? It seems like she failed!!