When invited to a meeting, people will immediately imagine an outcome of that meeting. If topics have been shared, the way they are described as well as what people hope for, will inform the way they think about the meeting.
They see the meeting from their point of view, with their needs and with their idea of what the group needs to achieve.
It doesn’t matter if people can name their expectations or not. If they don’t, they’ll have an implicit idea they’ll be using. This is the human desire to make sense of the world surrounding them as well as the activities they can feel subject to.
It also is what leads to judgment. Making sense without verifying and checking in with the others, assumes that one’s idea is the truth. Once that idea is shared as a truth, others will experience it as a judgment of their idea. That is, as a norm they are invited to comply with.