To achieve behavior change in our lives for several specific goals towards better well-being, various types intervention systems have been proposed. However, because of humans' bounded rationality, such explicit information provision for the users do not always reach their attention, thus fails the needed information for the behavior change. This paper propose new concepts "behavification"with which information system bypasses the user's cognitive, attentional and perceptive system by not notifying him/her and modifies the system behavior to directly influence the user's behavior under user's explicit advance permission. Through a series of group discussion and survey sessions with 19 participants, we investigated how the potential behavification users see its appropriateness to different application categories, killer application scenarios, and design guidelines and rationales for a behavification system to support such scenarios. We found total 58 application scenarios and propose 3 guidelines "advance user permission", "multi-modality"and "integration with real-world action/actuation".