Teaching has been described as an emerging community of practice. Within such professional communities, the processes of reflection and collaborative dialogue, or critical transformative dialogue, are central to the maintenance and improvement of professional practice for individuals, and the field. This paper reports on the challenges experienced by a group of first-year pre-service teachers engaging in a process of reflection and critique with peers, as they participated in a program focused on the development of core practices of teaching. These pre-service teachers' responses indicated their growing understanding of the importance of engaging in ongoing critical dialogue, as part of the "unnatural" aspects of teaching. The paper concludes with a reflection on the value of feedback from the earliest stages of professional learning. (Contains 2 tables.)