You assume what they say is the same as what they are thinking
The converse is also true. People saying something assume that people listening are understanding and thinking about the same thing. This is why it's important to write things down in details and as-unambiguous-as-you-can forms.
If you're in a meeting and someone puts up a slide deck with a 6 word bullet point that 'explains' what they want, that is a signal that literally no one understands the goal. If they put in a meeting without writing a one page doc about it, they don't understand it well enough to explain it.
And if your progression hangs off delivering that thing, you should by demanding that you get a clearer picture.
The converse is also true. People saying something assume that people listening are understanding and thinking about the same thing. This is why it's important to write things down in details and as-unambiguous-as-you-can forms.
If you're in a meeting and someone puts up a slide deck with a 6 word bullet point that 'explains' what they want, that is a signal that literally no one understands the goal. If they put in a meeting without writing a one page doc about it, they don't understand it well enough to explain it.
And if your progression hangs off delivering that thing, you should by demanding that you get a clearer picture.