Why does 'positive' management of pupils' behaviour matter? Well, by its very definition, it suggests clarity and confidence - both necessary attributes for successful teaching. However, taking a positive approach also helps us to sustain a classroom environment in which pupils feel safe and respected, and which is conducive to learning.
To promote positive behaviour, we should adhere to some well-documented key principles. (Indeed, my own posts include discussions about establishing rules and routines, and maintaining a learning climate.) But I believe that by adopting a positive mindset, and using consistently positive language, we can have a significant and long-term impact on a class's learning behaviour.
