The context of this study is the Danish upper secondary school, which has undergone remarkable changes during the past ten years. Cross-disciplinary activities have been introduced as a teaching principle in order to create new skills for future generations in the knowledge society, while team organization among teachers has become obligatory in order to ensure collaboration regarding a new era of student learning. The reform has been widely discussed among teachers and in the public media as well. Our research shows that the majority of teachers support the idea of teamwork, but also that there are differences in teachers' attitudes due to the diversity of interpretations of what constitutes good teaching and learning or what we call didactical values. We consider this an important discovery because it reveals that there is much resistance towards teamwork in the heterogeneous ways teachers understand their role as teacher. In this paper, we use data from a longitudinal study carried out in 2006-2009 to show that, in times of radical reforms such as the present, conflicts may be intensified exactly because of different didactical positions among teachers and between teachers and leaders in terms of how to create a viable connection between new structures and new teacher culture with the didactical values and practices that go along with them.