HMMMM i feel like tobito likes deidara's spontaneous and fiery nature. i feel like theyre more of the long con kind of planner and deidara adds the right amount of life to them

on the other hand i think deidara likes obito most for his loyalty. i think deidara thinks little of obito to begin with and with repeated trust and companionship deidara finds himself really dependent on obitos attention, but eventually he grows from it. deidara's needs are really childish as they first become lovers but grow as they get closer