On the other hand, it was Iroha that was a big surprise for me. I thought she's gonna be that idol-bitch type character (like Lunar in Seto no Hanayome, albeit serious) that would try to force her way into Hikigaya. But the development of their relationship, although not as deep as with Yui and Yukino, was done almost naturally.
I almost shipped her with Hikki at one point.