A Sensible Ranting of Crazy Ophelia

"Lord, we know what we are, but know not what we may be. God be at your table!"
-Ophelia Act 4.5 Lines 43-44

In essence, I think what Ophelia is saying is that we know who we are at the present moment, but what is too come that might shape and make us into different people, or at least our views or perceptions being tweaked, will be a mystery until the future comes about. The loss of her father was unexpected for. It's debatable that she didn't even know the true nature of her father; a spying, coniving, and controling old man. She did not see his death coming, but because of who he was, death found him and he was revealed in his true nature.