You hit an assumption wall because new information is being presented about changes shaping future for your organisation.
Assumption walls are brick walls in your thinking that prevent you from seeing and accepting the new in the present and constrain how you think about possible futures. You will know you have hit an assumption wall when you have a reaction like:
that will never happen! - meaning this is totally outside the realm of my experience so it must be wrong, and/or
that's rubbish! - meaning that conflicts with everything I know to be true so it must be wrong.
You hit an assumption wall because new information is being presented about changes shaping the future of your organisation. The assumption wall triggers a reaction that defends current ways of knowing and understanding the world. It's equivalent to the amygdala generating flight or fight responses when we face physical danger. Reactions like 'no, that won't happen' is a flight response - it means that you don't have to deal with the issue, that you can ignore it and return to your comfort zone of today's certainties.
Remember these well known…