When I was training to be a coach, they advised us to avoid asking our clients ‘Why?’ because it can evoke defensive justification. I ignore that bit of advice quite a lot.
For me, ‘Why ?’ is one of the most powerful questions we can ask. ‘Why is it done that way ?’, ‘Why do you think you did that ?”, ‘Why do I avoid the work I so desperately want to do ?’ - unless we ask why, we never get to the root of the problem, and so make finding a solution that much harder.
I love asking ‘Why ?’ In fact, I love it almost as asking ‘Why not…?’