“Can't”. The options killer.
Like “must”, “can’t” can either be the driving force to prove someone wrong or a contracting trap in inevitability.
You can't do x. Why? Because y will happen.
Well, what if you are okay with y happening. Is there actually anything stopping you from doing x is someone assuming that you don’t want y to happen? There is a big assumption of the other person that Y will definitely happen and that there are no other options. Do not take this as fact without investigating yourself. Can’t should be the red flag to trigger this action.
Like Harvey Spector in Suits always says, even if you have a gun pointed to your head, you still have a million options. Don’t rule them out without thinking about them. Can’t cuts them off before they have a chance. Don’t give in to others assumptions.