We understand more than we know.
Once upon a time, novelists of the 19th century, such as Charles Dickens, published in serial form.
Nothing changes instantaneously: in a gradually heating bathtub you'd be boiled to death before you knew it.
We thought we had such problems. How were we to know we were happy?
About no subject are poets tempted to lie so much as about their own lives.
For years I wanted to be older, and now I am.