People vary in their capacity to gain fresh ideas from any given speech, basically the variety of response is potentially as large as the number of people listening. No two people will have exactly the same total reaction, just as all people are individuals and have an identity of their own. Quite apart from the process of thought itself, each person has a memory or personal experience unique to themselves.
Common sense or common understanding results from the majority interpretation of any point of view or opinion.
If a listener is hearing a series of statements, they may be concentrating on a particular aspect, at any given point in time or considering several ideas collectively and even the whole topic as an entity.
If a person spends time thinking for too long, they may not comprehend the next items in the speech, but pick up on what is being spoken later.