Design is typically envisioned as aiming to improve situations for users, but this can fail. Failure can be the result of flawed design solutions, i.e. anti-patterns. Prior work in anti-patterns has largely focused on their characteristics. We instead concentrate on why they occur by outlining two processes that result in anti-patterns: 1) backfiring, and 2) favouring. The purpose of the paper is to help designers and researchers better understand how design processes can lead to negative impacts and to repentant designers by introducing a richer vocabulary for discussing such processes. We explore how anti-patterns evolve in HCI by specifically applying the vocabulary to examples of social media design. We believe that highlighting these processes will help the HCI community reflect on their own work and also raise awareness of the opportunities for avoiding anti-patterns. Our hope is that this will result in fewer negative experiences for designers and users alike.