I take the verse to say that when we're in heaven we'll "fully know even as we're fully known" to mean that we will have understanding that we cannot on this earth, in our fallen form obtain. Maybe we could obtain it - but could we handle or process the information? I have often thought that Deja Vu was evidence of our brain's capacity - a throwback to the original perfection of our creation before being tainted by a world of sin - that glimpses a margin of our being created in the image of the eternal Creator in our capacity for knowledge and non-linear perspective on time.
One thing I shall take the most joy in finally understanding is why some people are allowed to have children. Tonight, we had to let a little boy go home to a place where his mother was drunk earlier this evening, living with a man who they've only known a few weeks with a drug problem, and a million other things that would take too long to tell. He is the same age as my son and has seen and heard far too much at such a tender age, and spent way too many of his short span of days surviving. What we want to do is show him God's love - and yet every day he experiences the very opposite at home. The sound of my heart reverberates with the question "why?"