Writing about anything and using “I say,” the person is giving their own theory about something, but isn’t giving anything else to support that theory. Some readers will understand what the writer is talking about, but might still wonder how factual it is because of the lack of supporting evidence. Opposed to when the writer is stating a theory and could give supporting examples from other people (they say) in their statement, so that the reader can agree and relate to what the writer is saying.
When looking at art, some might only see what’s physically there, and say, “oh that’s nice” and move on to the other, not fully understanding the depths and beauty of it. On the contrary, one can look at an art piece, and it can take that person to another level of admiration with how meticulous the artist did his work. It can also make one understand and see the different types of symbolism that has been articulated in the art.